Audio Processing Algorithms

ABSTRACT

An example implementation involves a computing device transmitting, via a local area network, a command that instructs a playback device to play a particular audio signal. The example implementation also involves the computing device receiving data indicating a detected audio signal corresponding to playback of the particular audio signal by the playback device, where the detected audio signal includes a portion of the particular audio signal. The implementation further involves the computing device obtaining data indicating a predetermined audio characteristic and determining an audio processing algorithm based on the detected audio signal and the predetermined audio characteristic. The example implementation involves causing the playback device to apply the determined audio processing algorithm when playing audio via at least one speaker.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 120 to, and is acontinuation of, U.S. non-provisional patent application Ser. No.16/827,143, entitled “Audio Processing Algorithms,” which isincorporated herein by reference.

U.S. non-provisional patent application Ser. No. 16/827,143 claimspriority under 35 U.S.C. § 120 to, and is a continuation of, U.S.non-provisional patent application Ser. No. 15/955,545, entitled “AudioProcessing Algorithms,” and issued as U.S. Pat. No. 10,599,386 on Mar.24, 2020, which is incorporated herein by reference.

U.S. non-provisional patent application Ser. No. 15/955,545 claimspriority under 35 U.S.C. § 120 to, and is a continuation of, U.S.non-provisional patent application Ser. No. 14/481,505, entitled “AudioProcessing Algorithms,” and issued as U.S. Pat. No. 9,952,825 on Apr.24, 2018, which is incorporated herein by reference.

FIELD OF THE DISCLOSURE

The disclosure is related to consumer goods and, more particularly, tomethods, systems, products, features, services, and other elementsdirected to media playback or some aspect thereof.

BACKGROUND

Options for accessing and listening to digital audio in an out-loudsetting were limited until in 2003, when SONOS, Inc. filed for one ofits first patent applications, entitled “Method for Synchronizing AudioPlayback between Multiple Networked Devices,” and began offering a mediaplayback system for sale in 2005. The Sonos Wireless HiFi System enablespeople to experience music from a plethora of sources via one or morenetworked playback devices. Through a software control applicationinstalled on a smartphone, tablet, or computer, one can play what he orshe wants in any room that has a networked playback device.Additionally, using the controller, for example, different songs can bestreamed to each room with a playback device, rooms can be groupedtogether for synchronous playback, or the same song can be heard in allrooms synchronously.

Given the ever growing interest in digital media, there continues to bea need to develop consumer-accessible technologies to further enhancethe listening experience.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages of the presently disclosed technologymay be better understood with regard to the following description,appended claims, and accompanying drawings where:

FIG. 1 shows an example media playback system configuration in whichcertain embodiments may be practiced;

FIG. 2 shows a functional block diagram of an example playback device;

FIG. 3 shows a functional block diagram of an example control device;

FIG. 4 shows an example controller interface;

FIG. 5 shows an example flow diagram of a first method for maintaining adatabase of audio processing algorithms;

FIG. 6A shows an example portion of a first database of audio processingalgorithms;

FIG. 6B shows an example portion of a second database of audioprocessing algorithms;

FIG. 7 show an example flow diagram of a second method for maintaining adatabase of audio processing algorithms;

FIG. 8 shows an example playback zone within which a playback device maybe calibrated;

FIG. 9 shows an example flow diagram of a first method for determiningan audio processing algorithm based on one or more playback zonecharacteristics;

FIG. 10 shows an example flow diagram of a second method for determiningan audio processing algorithm based on one or more playback zonecharacteristics; and

FIG. 11 shows an example flow diagram for identifying an audioprocessing algorithm from a database of audio processing algorithms.

The drawings are for the purpose of illustrating example embodiments,but it is understood that the inventions are not limited to thearrangements and instrumentality shown in the drawings.

DETAILED DESCRIPTION I. Overview

When a playback device plays audio content in a playback zone, a qualityof the playback may depend on an acoustic characteristic of the playbackzone. In discussions herein, the playback zone may include one or moreplayback devices or groups of playback devices. The acousticcharacteristic of the playback zone may depend on a dimension of theplayback zone, types of furniture in the playback zone, and anarrangement of the furniture in the playback zone, among other factors.As such, different playback zones may have different acousticcharacteristics. Because a given model of the playback device may beused in a variety of different playback zones with different acousticcharacteristics, a single audio processing algorithm may not provide aconsistent quality of audio playback by the playback device in each ofthe different playback zones.

Examples discussed herein relate to determining an audio processingalgorithm for the playback device to apply based on acousticcharacteristics of a playback zone the playback device is in.Application of the determined audio processing algorithm by the playbackdevice when playing audio content in the playback zone may cause audiocontent rendered by the playback device in the playback zone to assume apredetermined audio characteristic, at least to some extent. In onecase, application of the audio processing algorithm may alter audioamplifications at one or more audio frequencies of the audio content.Other examples are also possible.

In one example, the database of audio processing algorithms may bemaintained, and an audio processing algorithm in the database may beidentified based on one or more characteristics of the playback zone.The one or more characteristics of the playback zone may include theacoustic characteristic of the playback zone, and/or one or more of adimension of the playback zone, a flooring and/or wall material of theplayback zone, and a number and/or types of furniture in the playbackzone, among other possibilities.

Maintaining the database of audio processing algorithms may involvedetermining at least one audio processing algorithm that corresponds tothe one or more characteristics of the playback zone, and adding thedetermined audio processing algorithm to the database. In one example,the database may be stored on one or more devices maintaining thedatabase, or one or more other devices. In discussions herein, unlessotherwise noted, the functions for maintaining the database may beperformed by one or more computing devices (i.e. servers), one or moreplayback devices, or one or more controller devices, among otherpossibilities. However, for simplicity, the one or more devicesperforming the functions may be generally referred to as a computingdevice.

In one example, determining such an audio processing algorithm mayinvolve the computing device determining an acoustic characteristic of aplayback zone. In one case, the playback zone may be a model room usedto simulate a playback zone within which the playback device may playaudio content. In such a case, one or more physical characteristics ofthe model room (i.e. dimensions, and floor and wall materials, etc.) maybe pre-determined. In another case, the playback zone may be a room in ahome of a user of the playback device. In such a case, the physicalcharacteristics of the playback zone may be provided by the user, or maybe otherwise unknown.

In one example, the computing device may cause the playback device inthe playback zone to play an audio signal. In one case, the played audiosignal may include audio content with frequencies covering substantiallyan entire frequency range renderable by the playback device. Theplayback device may subsequently detect an audio signal using amicrophone of the playback device. The microphone of the playbackdevices may be a built-in microphone of the playback device. In onecase, the detected audio signal may include a portion corresponding tothe played audio signal. For instance, the detected audio signal mayinclude a component of the played audio signal reflected within theplayback zone. The computing device may receive the detected audiosignal from the playback device, and determine an acoustic response ofthe playback zone based on the detected audio signal.

The computing device may then determine the acoustic characteristic ofthe playback zone by removing an acoustic characteristic of the playbackdevice from the acoustic response of the playback zone. The acousticcharacteristic of the playback device may be an acoustic characteristiccorresponding to a model of the playback device. In one case, theacoustic characteristic corresponding to the model of the playbackdevice may be determined based on audio signals played and detected by arepresentative playback device of the model in an anechoic chamber.

The computing device may then determine a corresponding audio processingalgorithm based on the determined acoustic characteristics of theplayback zone and a predetermined audio characteristic. Thepredetermined audio characteristics may involve a particular frequencyequalization that is considered good-sounding. The corresponding audioprocessing algorithm may be determined such that an application of thecorresponding audio processing algorithm by the playback device whenplaying audio content in the playback zone causes audio content renderedby the playback device in the playback zone to assume the predeterminedaudio characteristic, at least to some extent. For instance, if theacoustic characteristic of the playback zone is one in which aparticular audio frequency is more attenuated than other frequencies,the corresponding audio processing algorithm may involve an increasedamplification of the particular audio frequency. Other examples are alsopossible.

An association between the determined audio processing algorithm and theacoustic characteristic of the playback zone may then be stored as anentry in a database. In some cases, an association between the audioprocessing algorithm and one or more other characteristics of theplayback zone may additionally or alternatively be stored in thedatabase. For instance, if the playback zone is of a particulardimension, an association between the audio processing algorithm and theparticular room dimension may be stored in the database. Other examplesare also possible.

In one example, the database may be accessed by a computing device toidentify an audio processing algorithm for a playback device to apply ina playback zone. In one example, the computing device accessing thedatabase and identifying the audio processing algorithm may be the samecomputing device maintaining the database, as described above. Inanother example, the computing device may be a different computingdevice.

In some cases, accessing the database to identify an audio processingalgorithm for the playback device to apply in the playback zone may be apart of a calibration of the playback device. Such a calibration of theplayback device may be initiated by the playback device itself, by aserver in communication with the playback device, or by a controllerdevice. In one case, the calibration may be initiated because theplayback device is new and the calibration is part of an initial setupof the playback device. In another case, the playback device may havebeen repositioned, either within the same playback zone or from oneplayback zone to another. In a further case, the calibration may beinitiated by a user of the playback device, such as via the controllerdevice.

In one example, calibration of the playback device may involve thecomputing device prompting the user of the playback device to indicateone or more characteristics of the playback zone, such as an approximatedimension of the playback zone, flooring or wall material, and amount offurniture, among other possibilities. The computing device may promptthe user via a user interface on a controller device. Based on the oneor more characteristics of the playback zone as provided by the user, anaudio processing algorithm corresponding to the one or morecharacteristics of the playback zone may be identified in the database,and the playback device may accordingly apply the identified audioprocessing algorithm when playing audio content in the playback zone.

In another example, calibration of the playback device may involvedetermining an acoustic characteristic of the playback zone andidentifying a corresponding audio processing algorithm based on theacoustic characteristic of the playback zone. Determination of theacoustic characteristic of the playback zone may be similar to thatdescribed above. For instance, the playback device in the playback zonefor which the playback device is being calibrated for may play a firstaudio signal and subsequently detect using a microphone of the playbackdevice, a second audio signal. The second audio signal may then be basedupon to determine an acoustic characteristic of the playback zone. Basedon the determined acoustic characteristic, a corresponding audioprocessing algorithm may be identified in the database, and the playbackdevice may accordingly apply the identified audio processing algorithmwhen playing audio content in the playback zone. As indicated above,application of the corresponding audio processing algorithm by theplayback device when playing audio content in the playback zone maycause audio content rendered by the playback device in the playback zoneto assume the predetermined audio characteristic, at least to someextent.

While discussions of the calibration of the playback device discussedabove generally involve the database of audio processing algorithms, onehaving ordinary skill in the art will appreciate that the computingdevice may determine an audio processing algorithm for a playback zonewithout accessing the database. For instance, instead of identifying acorresponding audio processing algorithm in the database, the computingdevice may determine the audio processing algorithm by calculating theaudio processing algorithm based on the acoustic characteristic of theplayback zone (from the detected audio signal) and the predeterminedaudio characteristic, similar to that described above in connection tomaintenance of and generation of audio processing algorithm entries forthe database. Other examples are also possible.

In one case, the playback device to be calibrated may be one of aplurality of playback devices configured to synchronously play audiocontent in the playback zone. In such a case, determination of theacoustic characteristic of a playback zone may also involve audiosignals played by other playback devices in the playback zone. In oneexample, during the determination of the audio processing algorithm,each of the plurality of playback devices in the playback zone may playaudio signals at the same time such that the audio signal detected bythe microphone of the playback device may include a portioncorresponding to the audio signal played by the playback device, as wellas portions of audio signals played by the other playback devices in theplayback zone. An acoustic response of the playback zone may bedetermined based on the detected audio signal, and an acousticcharacteristic of the playback zone, including the other playbackdevices, may be determined by removing an acoustic characteristic of theplayback device being calibrated from the acoustic response of theplayback zone. An audio processing algorithm may then be calculated oridentified in the database based on the acoustic characteristic of theplayback zone and applied by the playback device.

In another case, two or more playback devices in the plurality ofplayback devices in the playback zone may each have a respectivebuilt-in microphone, and may each be individually calibrated accordingto the descriptions above. In one instance, the acoustic characteristicof the playback zone may be determined based on a collection of audiosignals detected by microphones of each of the two or more playbackdevices, and an audio processing algorithm corresponding to the acousticcharacteristic may be identified for each of the two or more playbackdevices. Other examples are also possible.

As indicated above, the present discussions involve determining an audioprocessing algorithm for the playback device to apply based on acousticcharacteristics of a particular playback zone the playback device is in.In one aspect, a computing device is provided. The computing deviceincludes a processor, and memory having stored thereon instructionsexecutable by the processor to cause the computing device to performfunctions. The functions include causing a playback device in a playbackzone to play a first audio signal, and receiving from the playbackdevice, data indicating a second audio signal detected by a microphoneof the playback device. The second audio signal includes a portioncorresponding to the first audio signal. The functions further includebased on the second audio signal and an acoustic characteristic of theplayback device, determining an audio processing algorithm, andtransmitting data indicating the determined audio processing algorithmto the playback device.

In another aspect, a computing device is provided. The computing deviceincludes a processor, and memory having stored thereon instructionsexecutable by the processor to cause the computing device to performfunctions. The functions include causing a first playback device to playa first audio signal in a playback zone, causing a second playbackdevice to play a second audio signal in the playback zone, and receivingfrom the first playback device, data indicating a third audio signaldetected by a microphone of the first playback device. The third audiosignal includes (i) a portion corresponding to the first audio signal,and (ii) a portion corresponding to the second audio signal played by asecond playback device. The functions also include based on the thirdaudio signal and an acoustic characteristic of the first playbackdevice, determining an audio processing algorithm, and transmitting dataindicating the determined audio processing algorithm to the firstplayback device.

In another aspect, a playback device is provided. The playback deviceincludes a processor, a microphone, and memory having stored thereoninstructions executable by the processor to cause the playback device toperform functions. The functions include while in a playback zone,playing a first audio signal, and detecting by the microphone, a secondaudio signal. The second audio signal includes a portion correspondingto the first audio signal. The functions also include based on thesecond audio signal and an acoustic characteristic of the playbackdevice, determining an audio processing algorithm, and applying thedetermined audio processing algorithm to audio data corresponding to amedia item when playing the media item in the playback zone.

In another aspect, a computing device is provided. The computing deviceincludes a processor, and memory having stored thereon instructionsexecutable by the processor to cause the computing device to performfunctions. The functions include causing a playback device in a playbackzone to play a first audio signal, and receiving data indicating asecond audio signal detected by a microphone of the playback device. Thesecond audio signal includes a portion corresponding to the first audiosignal played by the playback device. The functions also include basedon the second audio signal and a characteristic of the playback device,determining an acoustic characteristic of the playback zone, based onthe acoustic characteristic of the playback zone, determining an audioprocessing algorithm, and causing to be stored in a database, anassociation between the audio processing algorithm and the acousticcharacteristic of the playback zone.

In another aspect, a computing device is provided. The computing deviceincludes a processor, and memory having stored thereon instructionsexecutable by the processor to cause the computing device to performfunctions. The functions include causing a playback device in a playbackzone to play a first audio signal, and receiving (i) data indicating oneor more characteristics of a playback zone, and (ii) data indicating asecond audio signal detected by a microphone of the playback device. Thesecond audio signal includes a portion corresponding to the audio signalplayed by the playback device. The functions also include based on thesecond audio signal and a characteristic of the playback device,determining an audio processing algorithm, and cause to be stored in adatabase, an association between the determined audio processingalgorithm and at least one of the one or more characteristics of theplayback zone.

In another aspect, a computing device is provided. The computing deviceincludes a processor, and memory having stored thereon instructionsexecutable by the processor to cause the playback device to performfunctions. The functions include maintaining a database of (i) aplurality of audio processing algorithms and (ii) a plurality ofplayback zone characteristics. Each audio processing algorithm of theplurality of audio processing algorithms corresponds to at least oneplayback zone characteristic of the plurality of playback zonecharacteristics. The functions also include receiving data indicatingone or more characteristics of a playback zone, based on the data,identifying in the database, an audio processing algorithm, andtransmitting data indicating the identified audio processing algorithm.

While some examples described herein may refer to functions performed bygiven actors such as “users” and/or other entities, it should beunderstood that this is for purposes of explanation only. The claimsshould not be interpreted to require action by any such example actorunless explicitly required by the language of the claims themselves. Itwill be understood by one of ordinary skill in the art that thisdisclosure includes numerous other embodiments.

II. Example Operating Environment

FIG. 1 shows an example configuration of a media playback system 100 inwhich one or more embodiments disclosed herein may be practiced orimplemented. The media playback system 100 as shown is associated withan example home environment having several rooms and spaces, such as forexample, a master bedroom, an office, a dining room, and a living room.As shown in the example of FIG. 1, the media playback system 100includes playback devices 102-124, control devices 126 and 128, and awired or wireless network router 130.

Further discussions relating to the different components of the examplemedia playback system 100 and how the different components may interactto provide a user with a media experience may be found in the followingsections. While discussions herein may generally refer to the examplemedia playback system 100, technologies described herein are not limitedto applications within, among other things, the home environment asshown in FIG. 1. For instance, the technologies described herein may beuseful in environments where multi-zone audio may be desired, such as,for example, a commercial setting like a restaurant, mall or airport, avehicle like a sports utility vehicle (SUV), bus or car, a ship or boat,an airplane, and so on.

a. Example Playback Devices

FIG. 2 shows a functional block diagram of an example playback device200 that may be configured to be one or more of the playback devices102-124 of the media playback system 100 of FIG. 1. The playback device200 may include a processor 202, software components 204, memory 206,audio processing components 208, audio amplifier(s) 210, speaker(s) 212,microphone(s) 220, and a network interface 214 including wirelessinterface(s) 216 and wired interface(s) 218. In one case, the playbackdevice 200 may not include the speaker(s) 212, but rather a speakerinterface for connecting the playback device 200 to external speakers.In another case, the playback device 200 may include neither thespeaker(s) 212 nor the audio amplifier(s) 210, but rather an audiointerface for connecting the playback device 200 to an external audioamplifier or audio-visual receiver.

In one example, the processor 202 may be a clock-driven computingcomponent configured to process input data according to instructionsstored in the memory 206. The memory 206 may be a tangiblecomputer-readable medium configured to store instructions executable bythe processor 202. For instance, the memory 206 may be data storage thatcan be loaded with one or more of the software components 204 executableby the processor 202 to achieve certain functions. In one example, thefunctions may involve the playback device 200 retrieving audio data froman audio source or another playback device. In another example, thefunctions may involve the playback device 200 sending audio data toanother device or playback device on a network. In yet another example,the functions may involve pairing of the playback device 200 with one ormore playback devices to create a multi-channel audio environment.

Certain functions may involve the playback device 200 synchronizingplayback of audio content with one or more other playback devices.During synchronous playback, a listener will preferably not be able toperceive time-delay differences between playback of the audio content bythe playback device 200 and the one or more other playback devices. U.S.Pat. No. 8,234,395 entitled, “System and method for synchronizingoperations among a plurality of independently clocked digital dataprocessing devices,” which is hereby incorporated by reference, providesin more detail some examples for audio playback synchronization amongplayback devices.

The memory 206 may further be configured to store data associated withthe playback device 200, such as one or more zones and/or zone groupsthe playback device 200 is a part of, audio sources accessible by theplayback device 200, or a playback queue that the playback device 200(or some other playback device) may be associated with. The data may bestored as one or more state variables that are periodically updated andused to describe the state of the playback device 200. The memory 206may also include the data associated with the state of the other devicesof the media system, and shared from time to time among the devices sothat one or more of the devices have the most recent data associatedwith the system. Other embodiments are also possible.

The audio processing components 208 may include one or more ofdigital-to-analog converters (DAC), analog-to-digital converters (ADC),audio preprocessing components, audio enhancement components, and adigital signal processor (DSP), among others. In one embodiment, one ormore of the audio processing components 208 may be a subcomponent of theprocessor 202. In one example, audio content may be processed and/orintentionally altered by the audio processing components 208 to produceaudio signals. The produced audio signals may then be provided to theaudio amplifier(s) 210 for amplification and playback through speaker(s)212. Particularly, the audio amplifier(s) 210 may include devicesconfigured to amplify audio signals to a level for driving one or moreof the speakers 212. The speaker(s) 212 may include an individualtransducer (e.g., a “driver”) or a complete speaker system involving anenclosure with one or more drivers. A particular driver of thespeaker(s) 212 may include, for example, a subwoofer (e.g., for lowfrequencies), a mid-range driver (e.g., for middle frequencies), and/ora tweeter (e.g., for high frequencies). In some cases, each transducerin the one or more speakers 212 may be driven by an individualcorresponding audio amplifier of the audio amplifier(s) 210. In additionto producing analog signals for playback by the playback device 200, theaudio processing components 208 may be configured to process audiocontent to be sent to one or more other playback devices for playback.

Audio content to be processed and/or played back by the playback device200 may be received from an external source, such as via an audioline-in input connection (e.g., an auto-detecting 3.5 mm audio line-inconnection) or the network interface 214.

The microphone(s) 220 may include an audio sensor configured to convertdetected sounds into electrical signals. The electrical signal may beprocessed by the audio processing components 208 and/or the processor202. The microphone(s) 220 may be positioned in one or more orientationsat one or more locations on the playback device 200. The microphone(s)220 may be configured to detect sound within one or more frequencyranges. In one case, one or more of the microphone(s) 220 may beconfigured to detect sound within a frequency range of audio that theplayback device 200 is capable or rendering. In another case, one ormore of the microphone(s) 220 may be configured to detect sound within afrequency range audible to humans. Other examples are also possible.

The network interface 214 may be configured to facilitate a data flowbetween the playback device 200 and one or more other devices on a datanetwork. As such, the playback device 200 may be configured to receiveaudio content over the data network from one or more other playbackdevices in communication with the playback device 200, network deviceswithin a local area network, or audio content sources over a wide areanetwork such as the Internet. In one example, the audio content andother signals transmitted and received by the playback device 200 may betransmitted in the form of digital packet data containing an InternetProtocol (IP)-based source address and IP-based destination addresses.In such a case, the network interface 214 may be configured to parse thedigital packet data such that the data destined for the playback device200 is properly received and processed by the playback device 200.

As shown, the network interface 214 may include wireless interface(s)216 and wired interface(s) 218. The wireless interface(s) 216 mayprovide network interface functions for the playback device 200 towirelessly communicate with other devices (e.g., other playbackdevice(s), speaker(s), receiver(s), network device(s), control device(s)within a data network the playback device 200 is associated with) inaccordance with a communication protocol (e.g., any wireless standardincluding IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4Gmobile communication standard, and so on). The wired interface(s) 218may provide network interface functions for the playback device 200 tocommunicate over a wired connection with other devices in accordancewith a communication protocol (e.g., IEEE 802.3). While the networkinterface 214 shown in FIG. 2 includes both wireless interface(s) 216and wired interface(s) 218, the network interface 214 may in someembodiments include only wireless interface(s) or only wiredinterface(s).

In one example, the playback device 200 and one other playback devicemay be paired to play two separate audio components of audio content.For instance, playback device 200 may be configured to play a leftchannel audio component, while the other playback device may beconfigured to play a right channel audio component, thereby producing orenhancing a stereo effect of the audio content. The paired playbackdevices (also referred to as “bonded playback devices”) may further playaudio content in synchrony with other playback devices.

In another example, the playback device 200 may be sonicallyconsolidated with one or more other playback devices to form a single,consolidated playback device. A consolidated playback device may beconfigured to process and reproduce sound differently than anunconsolidated playback device or playback devices that are paired,because a consolidated playback device may have additional speakerdrivers through which audio content may be rendered. For instance, ifthe playback device 200 is a playback device designed to render lowfrequency range audio content (i.e. a subwoofer), the playback device200 may be consolidated with a playback device designed to render fullfrequency range audio content. In such a case, the full frequency rangeplayback device, when consolidated with the low frequency playbackdevice 200, may be configured to render only the mid and high frequencycomponents of audio content, while the low frequency range playbackdevice 200 renders the low frequency component of the audio content. Theconsolidated playback device may further be paired with a singleplayback device or yet another consolidated playback device.

By way of illustration, SONOS, Inc. presently offers (or has offered)for sale certain playback devices including a “PLAY:1,” “PLAY:3,”“PLAY:5,” “PLAYBAR,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Any otherpast, present, and/or future playback devices may additionally oralternatively be used to implement the playback devices of exampleembodiments disclosed herein. Additionally, it is understood that aplayback device is not limited to the example illustrated in FIG. 2 orto the SONOS product offerings. For example, a playback device mayinclude a wired or wireless headphone. In another example, a playbackdevice may include or interact with a docking station for personalmobile media playback devices. In yet another example, a playback devicemay be integral to another device or component such as a television, alighting fixture, or some other device for indoor or outdoor use.

b. Example Playback Zone Configurations

Referring back to the media playback system 100 of FIG. 1, theenvironment may have one or more playback zones, each with one or moreplayback devices. The media playback system 100 may be established withone or more playback zones, after which one or more zones may be added,or removed to arrive at the example configuration shown in FIG. 1. Eachzone may be given a name according to a different room or space such asan office, bathroom, master bedroom, bedroom, kitchen, dining room,living room, and/or balcony. In one case, a single playback zone mayinclude multiple rooms or spaces. In another case, a single room orspace may include multiple playback zones.

As shown in FIG. 1, the balcony, dining room, kitchen, bathroom, office,and bedroom zones each have one playback device, while the living roomand master bedroom zones each have multiple playback devices. In theliving room zone, playback devices 104, 106, 108, and 110 may beconfigured to play audio content in synchrony as individual playbackdevices, as one or more bonded playback devices, as one or moreconsolidated playback devices, or any combination thereof. Similarly, inthe case of the master bedroom, playback devices 122 and 124 may beconfigured to play audio content in synchrony as individual playbackdevices, as a bonded playback device, or as a consolidated playbackdevice.

In one example, one or more playback zones in the environment of FIG. 1may each be playing different audio content. For instance, the user maybe grilling in the balcony zone and listening to hip hop music beingplayed by the playback device 102 while another user may be preparingfood in the kitchen zone and listening to classical music being playedby the playback device 114. In another example, a playback zone may playthe same audio content in synchrony with another playback zone. Forinstance, the user may be in the office zone where the playback device118 is playing the same rock music that is being playing by playbackdevice 102 in the balcony zone. In such a case, playback devices 102 and118 may be playing the rock music in synchrony such that the user mayseamlessly (or at least substantially seamlessly) enjoy the audiocontent that is being played out-loud while moving between differentplayback zones. Synchronization among playback zones may be achieved ina manner similar to that of synchronization among playback devices, asdescribed in previously referenced U.S. Pat. No. 8,234,395.

As suggested above, the zone configurations of the media playback system100 may be dynamically modified, and in some embodiments, the mediaplayback system 100 supports numerous configurations. For instance, if auser physically moves one or more playback devices to or from a zone,the media playback system 100 may be reconfigured to accommodate thechange(s). For instance, if the user physically moves the playbackdevice 102 from the balcony zone to the office zone, the office zone maynow include both the playback device 118 and the playback device 102.The playback device 102 may be paired or grouped with the office zoneand/or renamed if so desired via a control device such as the controldevices 126 and 128. On the other hand, if the one or more playbackdevices are moved to a particular area in the home environment that isnot already a playback zone, a new playback zone may be created for theparticular area.

Further, different playback zones of the media playback system 100 maybe dynamically combined into zone groups or split up into individualplayback zones. For instance, the dining room zone and the kitchen zone114 may be combined into a zone group for a dinner party such thatplayback devices 112 and 114 may render audio content in synchrony. Onthe other hand, the living room zone may be split into a television zoneincluding playback device 104, and a listening zone including playbackdevices 106, 108, and 110, if the user wishes to listen to music in theliving room space while another user wishes to watch television.

c. Example Control Devices

FIG. 3 shows a functional block diagram of an example control device 300that may be configured to be one or both of the control devices 126 and128 of the media playback system 100. As shown, the control device 300may include a processor 302, memory 304, a network interface 306, a userinterface 308, and microphone(s) 310. In one example, the control device300 may be a dedicated controller for the media playback system 100. Inanother example, the control device 300 may be a network device on whichmedia playback system controller application software may be installed,such as for example, an iPhone™, iPad™ or any other smart phone, tabletor network device (e.g., a networked computer such as a PC or Mac™).

The processor 302 may be configured to perform functions relevant tofacilitating user access, control, and configuration of the mediaplayback system 100. The memory 304 may be configured to storeinstructions executable by the processor 302 to perform those functions.The memory 304 may also be configured to store the media playback systemcontroller application software and other data associated with the mediaplayback system 100 and the user.

The microphone(s) 310 may include an audio sensor configured to convertdetected sounds into electrical signals. The electrical signal may beprocessed by the processor 302. In one case, if the control device 300is a device that may also be used as a means for voice communication orvoice recording, one or more of the microphone(s) 310 may be amicrophone for facilitating those functions. For instance, the one ormore of the microphone(s) 310 may be configured to detect sound within afrequency range that a human is capable of producing and/or a frequencyrange audible to humans. Other examples are also possible.

In one example, the network interface 306 may be based on an industrystandard (e.g., infrared, radio, wired standards including IEEE 802.3,wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n,802.11ac, 802.15, 4G mobile communication standard, and so on). Thenetwork interface 306 may provide a means for the control device 300 tocommunicate with other devices in the media playback system 100. In oneexample, data and information (e.g., such as a state variable) may becommunicated between control device 300 and other devices via thenetwork interface 306. For instance, playback zone and zone groupconfigurations in the media playback system 100 may be received by thecontrol device 300 from a playback device or another network device, ortransmitted by the control device 300 to another playback device ornetwork device via the network interface 306. In some cases, the othernetwork device may be another control device.

Playback device control commands such as volume control and audioplayback control may also be communicated from the control device 300 toa playback device via the network interface 306. As suggested above,changes to configurations of the media playback system 100 may also beperformed by a user using the control device 300. The configurationchanges may include adding/removing one or more playback devices to/froma zone, adding/removing one or more zones to/from a zone group, forminga bonded or consolidated player, separating one or more playback devicesfrom a bonded or consolidated player, among others. Accordingly, thecontrol device 300 may sometimes be referred to as a controller, whetherthe control device 300 is a dedicated controller or a network device onwhich media playback system controller application software isinstalled.

The user interface 308 of the control device 300 may be configured tofacilitate user access and control of the media playback system 100, byproviding a controller interface such as the controller interface 400shown in FIG. 4. The controller interface 400 includes a playbackcontrol region 410, a playback zone region 420, a playback status region430, a playback queue region 440, and an audio content sources region450. The user interface 400 as shown is just one example of a userinterface that may be provided on a network device such as the controldevice 300 of FIG. 3 (and/or the control devices 126 and 128 of FIG. 1)and accessed by users to control a media playback system such as themedia playback system 100. Other user interfaces of varying formats,styles, and interactive sequences may alternatively be implemented onone or more network devices to provide comparable control access to amedia playback system.

The playback control region 410 may include selectable (e.g., by way oftouch or by using a cursor) icons to cause playback devices in aselected playback zone or zone group to play or pause, fast forward,rewind, skip to next, skip to previous, enter/exit shuffle mode,enter/exit repeat mode, enter/exit cross fade mode. The playback controlregion 410 may also include selectable icons to modify equalizationsettings, and playback volume, among other possibilities.

The playback zone region 420 may include representations of playbackzones within the media playback system 100. In some embodiments, thegraphical representations of playback zones may be selectable to bringup additional selectable icons to manage or configure the playback zonesin the media playback system, such as a creation of bonded zones,creation of zone groups, separation of zone groups, and renaming of zonegroups, among other possibilities.

For example, as shown, a “group” icon may be provided within each of thegraphical representations of playback zones. The “group” icon providedwithin a graphical representation of a particular zone may be selectableto bring up options to select one or more other zones in the mediaplayback system to be grouped with the particular zone. Once grouped,playback devices in the zones that have been grouped with the particularzone will be configured to play audio content in synchrony with theplayback device(s) in the particular zone. Analogously, a “group” iconmay be provided within a graphical representation of a zone group. Inthis case, the “group” icon may be selectable to bring up options todeselect one or more zones in the zone group to be removed from the zonegroup. Other interactions and implementations for grouping andungrouping zones via a user interface such as the user interface 400 arealso possible. The representations of playback zones in the playbackzone region 420 may be dynamically updated as playback zone or zonegroup configurations are modified.

The playback status region 430 may include graphical representations ofaudio content that is presently being played, previously played, orscheduled to play next in the selected playback zone or zone group. Theselected playback zone or zone group may be visually distinguished onthe user interface, such as within the playback zone region 420 and/orthe playback status region 430. The graphical representations mayinclude track title, artist name, album name, album year, track length,and other relevant information that may be useful for the user to knowwhen controlling the media playback system via the user interface 400.

The playback queue region 440 may include graphical representations ofaudio content in a playback queue associated with the selected playbackzone or zone group. In some embodiments, each playback zone or zonegroup may be associated with a playback queue containing informationcorresponding to zero or more audio items for playback by the playbackzone or zone group. For instance, each audio item in the playback queuemay comprise a uniform resource identifier (URI), a uniform resourcelocator (URL) or some other identifier that may be used by a playbackdevice in the playback zone or zone group to find and/or retrieve theaudio item from a local audio content source or a networked audiocontent source, possibly for playback by the playback device.

In one example, a playlist may be added to a playback queue, in whichcase information corresponding to each audio item in the playlist may beadded to the playback queue. In another example, audio items in aplayback queue may be saved as a playlist. In a further example, aplayback queue may be empty, or populated but “not in use” when theplayback zone or zone group is playing continuously streaming audiocontent, such as Internet radio that may continue to play untilotherwise stopped, rather than discrete audio items that have playbackdurations. In an alternative embodiment, a playback queue can includeInternet radio and/or other streaming audio content items and be “inuse” when the playback zone or zone group is playing those items. Otherexamples are also possible.

When playback zones or zone groups are “grouped” or “ungrouped,”playback queues associated with the affected playback zones or zonegroups may be cleared or re-associated. For example, if a first playbackzone including a first playback queue is grouped with a second playbackzone including a second playback queue, the established zone group mayhave an associated playback queue that is initially empty, that containsaudio items from the first playback queue (such as if the secondplayback zone was added to the first playback zone), that contains audioitems from the second playback queue (such as if the first playback zonewas added to the second playback zone), or a combination of audio itemsfrom both the first and second playback queues. Subsequently, if theestablished zone group is ungrouped, the resulting first playback zonemay be re-associated with the previous first playback queue, or beassociated with a new playback queue that is empty or contains audioitems from the playback queue associated with the established zone groupbefore the established zone group was ungrouped. Similarly, theresulting second playback zone may be re-associated with the previoussecond playback queue, or be associated with a new playback queue thatis empty, or contains audio items from the playback queue associatedwith the established zone group before the established zone group wasungrouped. Other examples are also possible.

Referring back to the user interface 400 of FIG. 4, the graphicalrepresentations of audio content in the playback queue region 440 mayinclude track titles, artist names, track lengths, and other relevantinformation associated with the audio content in the playback queue. Inone example, graphical representations of audio content may beselectable to bring up additional selectable icons to manage and/ormanipulate the playback queue and/or audio content represented in theplayback queue. For instance, a represented audio content may be removedfrom the playback queue, moved to a different position within theplayback queue, or selected to be played immediately, or after anycurrently playing audio content, among other possibilities. A playbackqueue associated with a playback zone or zone group may be stored in amemory on one or more playback devices in the playback zone or zonegroup, on a playback device that is not in the playback zone or zonegroup, and/or some other designated device.

The audio content sources region 450 may include graphicalrepresentations of selectable audio content sources from which audiocontent may be retrieved and played by the selected playback zone orzone group. Discussions pertaining to audio content sources may be foundin the following section.

d. Example Audio Content Sources

As indicated previously, one or more playback devices in a zone or zonegroup may be configured to retrieve for playback audio content (e.g.according to a corresponding URI or URL for the audio content) from avariety of available audio content sources. In one example, audiocontent may be retrieved by a playback device directly from acorresponding audio content source (e.g., a line-in connection). Inanother example, audio content may be provided to a playback device overa network via one or more other playback devices or network devices.

Example audio content sources may include a memory of one or moreplayback devices in a media playback system such as the media playbacksystem 100 of FIG. 1, local music libraries on one or more networkdevices (such as a control device, a network-enabled personal computer,or a networked-attached storage (NAS), for example), streaming audioservices providing audio content via the Internet (e.g., the cloud), oraudio sources connected to the media playback system via a line-in inputconnection on a playback device or network devise, among otherpossibilities.

In some embodiments, audio content sources may be regularly added orremoved from a media playback system such as the media playback system100 of FIG. 1. In one example, an indexing of audio items may beperformed whenever one or more audio content sources are added, removedor updated. Indexing of audio items may involve scanning foridentifiable audio items in all folders/directory shared over a networkaccessible by playback devices in the media playback system, andgenerating or updating an audio content database containing metadata(e.g., title, artist, album, track length, among others) and otherassociated information, such as a URI or URL for each identifiable audioitem found. Other examples for managing and maintaining audio contentsources may also be possible.

The above discussions relating to playback devices, controller devices,playback zone configurations, and media content sources provide onlysome examples of operating environments within which functions andmethods described below may be implemented. Other operating environmentsand configurations of media playback systems, playback devices, andnetwork devices not explicitly described herein may also be applicableand suitable for implementation of the functions and methods.

III. Maintaining a Database of Signal Processing Algorithms

As indicated above, some examples discussed herein relate to maintaininga database of audio processing algorithms. In some cases, maintenance ofa database may further involve generating and/or updating entries ofaudio processing algorithms for the database. Each of the audioprocessing algorithms in the database may correspond to one or morecharacteristics of the playback zone. In one example, the one or morecharacteristics of the playback zone may include an acousticcharacteristic of the playback zone. While the discussions below maygenerally relate to determining an audio processing algorithm to bestored as an entry in a database, one having ordinary skill in the artwill appreciate that similar functions may also be performed to updateexisting entries in the database. The database may be accessed toidentify an audio processing algorithm for a playback device to applywhen playing audio content in a particular playback zone.

a. Example Database of Audio Processing Algorithms and CorrespondingAcoustic Characteristics of Playback Zones

FIG. 5 shows an example flow diagram of a method 500 for maintaining adatabase of audio processing algorithms and playback zone acousticcharacteristics. As indicated above, maintaining a database of audioprocessing algorithms may involve determining audio processingalgorithms to be stored in the database. Method 500 shown in FIG. 5presents an embodiment of a method that can be implemented within anoperating environment involving, for example, the media playback system100 of FIG. 1, one or more of the playback device 200 of FIG. 2, and oneor more of the control device 300 of FIG. 3. In one example, the method500 may be performed by a computing device that is in communication witha media playback system, such as the media playback system 100. Inanother example, some or all of the functions of method 500 mayalternatively be performed by one or more other computing devices, suchas one or more servers, one or more playback devices, and/or one or morecontroller devices.

Method 500 may include one or more operations, functions, or actions asillustrated by one or more of blocks 502-510. Although the blocks areillustrated in sequential order, these blocks may also be performed inparallel, and/or in a different order than those described herein. Also,the various blocks may be combined into fewer blocks, divided intoadditional blocks, and/or removed based upon the desired implementation.In addition, for the method 500 and other processes and methodsdisclosed herein, the flowchart shows functionality and operation of onepossible implementation of present embodiments. In this regard, eachblock may represent a module, a segment, or a portion of program code,which includes one or more instructions executable by a processor forimplementing specific logical functions or steps in the process. Theprogram code may be stored on any type of computer readable medium, forexample, such as a storage device including a disk or hard drive.

The computer readable medium may include non-transitory computerreadable medium, for example, such as computer-readable media thatstores data for short periods of time like register memory, processorcache and Random Access Memory (RAM). The computer readable medium mayalso include non-transitory media, such as secondary or persistent longterm storage, like read only memory (ROM), optical or magnetic disks,compact-disc read only memory (CD-ROM), for example. The computerreadable media may also be any other volatile or non-volatile storagesystems. The computer readable medium may be considered a computerreadable storage medium, for example, or a tangible storage device. Inaddition, for the method 500 and other processes and methods disclosedherein, each block may represent circuitry that is wired to perform thespecific logical functions in the process.

As shown in FIG. 5, the method 500 involves the computing device causinga playback device in a playback zone to play a first audio signal atblock 502, receiving data indicating a second audio signal detected by amicrophone of the playback device at block 504, based on the secondaudio signal and a characteristic of the playback device, determining anacoustic characteristic of the playback zone at block 506, based on theacoustic characteristic of the playback zone, determining an audioprocessing algorithm at block 508, and causing to be stored in adatabase, an association between the audio processing algorithm and theacoustic characteristic of the playback zone at block 510.

As discussed previously, the database may be accessed to identify anaudio processing algorithm for a playback device to apply when playingaudio content in a playback zone. As such, in one example, the method500 may be performed for a variety of different playback zones to builda database of audio processing algorithms corresponding to a variety ofdifferent playback environments.

At block 502, the method 500 involves causing a playback device in aplayback zone to play a first audio signal. The playback device may be aplayback device similar to the playback device 200 shown in FIG. 2. Inone case, the computing device may cause the playback device to play thefirst audio signal by sending a command to play the first audio signal.In another case, the computing device may also provide to the playbackdevice the first audio signal to be played.

In one example, the first audio signal may be used for determining anacoustic response of the playback zone. As such, the first audio signalmay be a test signal or measurement signal representative of audiocontent that may be played by the playback device during regular use bya user. Accordingly, the first audio signal may include audio contentwith frequencies substantially covering a renderable frequency range ofthe playback device or a frequency range audible to a human.

In one example, the playback zone may be a playback zone representativeof one of a plurality of playback environments within which the playbackdevice may play audio content during regular use by a user. Referring toFIG. 1, the playback zone may be representative of any one of thedifferent rooms and zone groups in the media playback system 100. Forinstance, the playback zone may be representative of the dining room.

In one case, the playback zone may be a model playback zone built tosimulate a listening environment within which the playback device mayplay audio content. In one instance, the playback zone may be one of aplurality of playback zones built to simulate the plurality of playbackenvironments. The plurality of playback zones may be built for purposesof populating such a database of audio processing algorithms. In such acase, certain characteristics of the playback zone may be predeterminedand/or known. For instance, a dimension of the playback zone, a flooringor wall material of the playback zone (or other features that mayaffects an audio reflectivity characteristic of the playback zone), anumber of furniture in the playback zone, or sizes and types of thefurniture in the playback zone, among other possibilities may becharacteristics of the playback zone that may be predetermined and/orknown.

In another case, the playback zone may be a room within a household of auser of the playback device. For instance, as part of building thedatabase, users of the playback device, such as customers and/ortesters, may be invited to use their playback devices to perform thefunctions of method 500 to build the database. In some cases, thecertain characteristics of the user playback zone may not be known. Insome other cases, some or all of the certain characteristics of the userplayback zone may be provided by the user. The database populated fromperforming the functions of method 500 may include entries based onsimulated playback zones and/or user playback zones.

While block 502 involves the computing device causing the playbackdevice to play the first audio signal, one having ordinary skill in theart will appreciate that playback of the first audio signal by theplayback device may not necessarily be caused or initiated by thecomputing device. For instance, a controller device may send a commandto the playback device to cause the playback device to play the firstaudio signal. In another instance, the playback device may play thefirst audio signal without receiving a command from the computing deviceor controller. Other examples are also possible.

At block 504, the method 500 involves receiving data indicating a secondaudio signal detected by a microphone of the playback device. Asindicated above, the playback device may be a playback device similar tothe playback device 200 shown in FIG. 2. As such, the microphone may bethe microphone 220. In one example, the computing device may receive thedata from the playback device. In another example, the computing devicemay receive the data via another playback device, a controller device,or another server.

While the playback device is playing the first audio signal, or shortlythereafter, the microphone of the playback device may detect the secondaudio signal. The second audio signal may include detectable audiosignals present in the playback zone. For instance, the second audiosignal may include a portion corresponding to the first audio signalplayed by the playback device.

In one example, the computing device may receive data indicating thedetected second audio signal from the playback device as a media streamwhile the microphone detects the second audio signal. In anotherexample, the computing device may receive from the playback device, dataindicating the second audio signal once detection of the first audiosignal by the microphone of the playback device is complete. In eithercase, the playback device may process the detected second audio signal(via an audio processing component, such as the audio processingcomponent 208 of the playback device 200) to generate the dataindicating the second audio signal, and transmit the data to thecomputing device. In one instance, generating the data indicating thesecond audio signal may involve converting the second audio signal froman analog signal to a digital signal. Other examples are also possible.

At block 506, the method 500 involves based on the second audio signaland a characteristic of the playback device, determining an acousticcharacteristic of the playback zone. As indicated above, the secondaudio signal may include portion corresponding to the first audio signalplayed by the playback device in the playback zone.

The characteristic of the playback device may include one or more of anacoustic characteristic of the playback device, specifications of theplayback device (i.e. number of transducers, frequency range, amplifierwattage, etc.), and a model of the playback device. In some cases, theacoustic characteristic of the playback device and/or specifications ofthe playback device may be associated with the model of the playbackdevice. For instance, a particular model of playback devices may havesubstantially the same specifications and acoustic characteristics. Inone example, a database of models of playback devices, acousticcharacteristics of the models of playback devices, and/or specificationsof the models of playback devices may be maintained on the computingdevice or another device in communication with the computing device.

In one example, an acoustic response from the playback device playingthe first audio signal in the playback zone may be represented by arelationship between the first audio signal and the second audio signal.Mathematically, if the first audio signal is f(t), the second audiosignal is s(t), and the acoustic response of the playback device playingthe first audio signal in the playback zone is h_(r)(t), then

s(t)=f(t)⊗h _(r)(t)  (1)

where ⊗ represents the mathematical function of convolution. As such,given the second audio signal s(t) that is detected by the microphone ofthe playback device, and the first signal f(t) that was played by theplayback device, h_(r)(t) may be calculated.

In one case, because the first audio signal f(t) was played by theplayback device, the acoustic response h_(r)(t) may include (i) anacoustic characteristic of the playback device and (ii) the acousticcharacteristic of the playback zone that is independent of the playbackdevice. Mathematically, this relationship may be represented as

h _(r)(t)=h _(p)(t)+h _(room)(t)  (2)

where h_(p)(t) is the acoustic characteristic of the playback device,and h_(room)(t) is the acoustic characteristic of the playback zone,independent of the playback device. As such, the acoustic characteristicof the playback zone that is independent of the playback device may bedetermined by removing the acoustic characteristic of the playbackdevice from the acoustic response of the playback zone to the firstaudio signal played by the playback device. In other words,

h _(room)(t)=h _(r)(t)−h _(p)(t).  (3)

In one example, the acoustic characteristic of the playback deviceh_(p)(t) may be determined by placing the playback device or arepresentative playback device of the same model in an anechoic chamber,causing the playback device to play a measurement signal in the anechoicchamber, and detecting a response signal by the microphone of theplayback device. The measurement signal played by the playback device inthe anechoic chamber may be similar to the first audio signal f(t)discussed above. For instance, the measurement signal may have audiocontent with frequencies substantially covering the renderable frequencyrange of the playback device or the frequency range audible to a human.

The acoustic characteristic of the playback device h_(p)(t) mayrepresent a relationship between the played measurement signal and thedetected response signal. For instance, if the measurement signal has afirst signal magnitude at a particular frequency, and the detectedresponse signal has a second signal magnitude at the particularfrequency different from the first signal magnitude, then the acousticcharacteristic of the playback device h_(p)(t) may indicate signalamplification or attenuation at the particular frequency.

Mathematically, if the measurement signal is x(t), the detected responsesignal is y(t), and the acoustic characteristic of the playback devicein the anechoic chamber is h_(p)(t), then

y(t)=x(t)⊗h _(p)(t).  (4)

Accordingly, h_(p)(t) may be calculated based on the measurement signalx(t) and the detected response signal y(t). As indicated above, h_(p)(t)may be the representative acoustic characteristic for playback devicesof the same model as that used in the anechoic chamber.

In one example, as indicated above, the reference acousticcharacteristic h_(p)(t) may be stored in association with the model ofthe playback device and/or specifications of the playback device. In oneexample, h_(p)(t) maybe stored on the computing device. In anotherexample, h_(p)(t) may be stored on the playback device and otherplayback devices of the same model. In a further case, an inverse ofh_(p)(t), represented as h_(p) ⁻¹(t), may be stored instead of h_(p)(t).

Referring back to block 506, the acoustic characteristic of the playbackzone h_(room)(t) may accordingly be determined based on the first audiosignal f(t), the second audio signal s(t), and the acousticcharacteristic h_(p)(t) of the playback device. In one example, theinverse of the acoustic characteristic of the playback device, h_(p)⁻¹(t) may be applied to the equation (2). In other words,

$\begin{matrix}\begin{matrix}{{{h_{p}^{- 1}(t)} \otimes {h_{r}(t)}} = {{{h_{p}^{- 1}(t)} \otimes {h_{p}(t)}} + {{h_{p}^{- 1}(t)} \otimes {h_{room}(t)}}}} \\{= {{I(t)} + {{h_{p}^{- 1}(t)} \otimes {h_{room}(t)}}}}\end{matrix} & (5)\end{matrix}$

where I(t) is an impulse signal. The acoustic characteristic of theplayback zone h_(room)(t) may then be simplified as:

h _(room)(t)=h _(p)(t)⊗[h ⁻¹ _(p)(t)⊗h _(r)(t)−I(t)].  (6)

At block 506, the method 500 involves based on the acousticcharacteristic of the playback zone and a predetermined audio signal,determining an audio processing algorithm. In one example, the audioprocessing algorithm may be determined such that an application of thedetermined audio processing algorithm by the playback device whenplaying the first audio signal in the playback zone may produce a thirdaudio signal having an audio characteristic substantially the same as apredetermined audio characteristic, or assumes the predetermined audiocharacteristic, at least to some extent.

In one example, the predetermined audio characteristic may be an audiofrequency equalization that is considered good-sounding. In one case,the predetermined audio characteristic may involve an equalization thatis substantially even across the renderable frequency range of theplayback device. In another case, the predetermined audio characteristicmay involve an equalization that is considered pleasing to a typicallistener. In a further case, the predetermined audio characteristic mayinvolve a frequency response that is considered suitable for aparticular genre of music.

Whichever the case, the computing device may determine the audioprocessing algorithm based on the acoustic characteristic and thepredetermined audio characteristic. In one example, if the acousticcharacteristic of the playback zone is one in which a particular audiofrequency is more attenuated than other frequencies, and thepredetermined audio characteristic involves an equalization in which theparticular audio frequency is minimally attenuated, the correspondingaudio processing algorithm may involve an increased amplification at theparticular audio frequency.

If the predetermined audio characteristic is represented by apredetermined audio signal z(t), and the audio processing algorithm isrepresented by p(t), a relationship between the predetermined audiosignal z(t), the audio processing algorithm, and the acousticcharacteristic of the playback zone h_(room)(t) may be mathematicallydescribed as:

z(t)=p(t)⊗h _(room)(t).  (7)

Accordingly, the audio processing algorithm p(t) may be mathematicallydescribed as:

p(t)=z(t)⊗h _(room) ⁻¹(t)  (8)

In some cases, determining the audio processing algorithm may involvedetermining one or more parameters for the audio processing algorithm(i.e. coefficients for p(t)). For instance, the audio processingalgorithm may include certain signal amplification gains at certaincorresponding frequencies of the audio signal. As such, parametersindicating the certain signal amplification and/or the certaincorresponding frequencies of the audio signal may be identified todetermine the audio processing algorithm p(t).

At block 510, the method 500 involves causing to be stored in adatabase, an association between the audio processing algorithm and theacoustic characteristic of the playback zone. As such, an entry thatincludes the acoustic characteristic of the playback zone h_(room)(t),and the corresponding audio processing algorithm p(t) as determined atblock 504 and 506 may be added to the database. In one example, thedatabase may be stored on local memory storage of the computing device.In another example, if the database is stored on another device, thecomputing device may transmit the audio processing algorithm andacoustic characteristic of the playback zone to the other device to bestored in the database. Other examples are also possible.

As indicated above, the playback zone for which the audio processingalgorithm was determined may be a model playback zone used to simulate alistening environment within which the playback device may play audiocontent, or a room of a user of the playback device. In some cases, thedatabase may include entries generated based on audio signals played anddetected within model playback zones as well as entries generated basedon audio signals played and detected within a room of a user of aplayback device.

FIG. 6A shows an example portion of a database 600 of audio processingalgorithms, within which the audio processing algorithm p(t) determinedin the discussions above may be stored. As shown, the portion of thedatabase 600 may include a plurality of entries 602-608. The entry 602may include a playback zone acoustic characteristic h_(room) ⁻¹(t)−1.The acoustic characteristic h_(room) ⁻¹(t)−1 may be a mathematicalrepresentation of the acoustic characteristic of a playback zone, ascalculated based on an audio signal detected by a playback device and acharacteristic of the playback device as described above. Correspondingto the acoustic characteristic h_(room) ⁻¹(t)−1 in entry 602 may becoefficients w₁, x₁, y₁, and z₁ for an audio processing algorithmdetermined based on the acoustic characteristic h_(room) ⁻¹(t)−1 and apredetermined audio characteristic, as also described above.

As further shown, entry 604 of the database 600 may include a playbackzone acoustic characteristic h_(room) ⁻¹(t)−2 and processing algorithmcoefficients w₂, x₂, y₂, and z₂, entry 606 of the database 600 mayinclude a playback zone acoustic characteristic h_(room) ⁻¹(t)−3 andprocessing algorithm coefficients w₃, x₃, y₃, and z₃, and entry 608 ofthe database 600 may include a playback zone acoustic characteristich_(room) ⁻¹(t)−4 and processing algorithm coefficients w₄, x₄, y₄, andz₄.

One having ordinary skill in the art will appreciate that database 600is just one example of a database that may be populated and maintainedby performing the functions of method 500. In one example, the playbackzone acoustic characteristics may be stored in a different format ormathematical state (i.e. inversion vs non-inverse functions). In anotherexample, the audio processing algorithms may be stored as functionand/or equalization functions. Other examples are also possible.

In one example, some of the functions described above may be performedmultiple times for the same playback device in the same playback zone todetermine the acoustic characteristic of the playback zone h_(room)(t)and the corresponding processing algorithm p(t). For instance, blocks502-506 may be performed multiple times to determine a plurality ofacoustic characteristics of the playback zone. A combined (i.e.averaged) acoustic characteristic of the playback zone may be determinedfrom the plurality of acoustic characteristics, and the correspondingprocessing algorithm p(t) may be determined based on the combinedacoustic characteristic of the playback zone. An association between thecorresponding processing algorithm p(t) and the acoustic characteristicof the playback zone h_(room)(t) or h_(room) ⁻¹(t) may then be stored inthe database. In some cases, the first audio signal played by theplayback device in the playback zone may be substantially the same audiosignal during each of the iterations of the functions. In some othercases, the first audio signal played by the playback device in theplayback zone may be a different audio signal for some or each of theiterations of the functions. Other examples are also possible.

The method 500 as described above (or some variation of the method 500)may further be performed to generate other entries in the database. Forinstance, given that the playback device is a first playback device, theplayback zone is a first playback zone, and the audio processingalgorithm is a first audio processing algorithm, the method 500 mayadditionally or alternatively be performed using a second playbackdevice in a second playback zone. In one example, the second playbackdevice may play a fourth audio signal in the second playback zone and amicrophone of the second playback device may detected a fifth audiosignal that includes a portion of the fourth audio signal played by thesecond playback device. The computing device may then receive dataindicating the fifth audio signal and determine an acousticcharacteristic of the second playback zone based on the fifth audiosignal and a characteristic of the second playback device.

Based on the acoustic characteristic of the second playback zone, thecomputing device may determine a second audio processing algorithm suchthat applying of the determined second audio processing algorithm by thesecond playback device when playing the fourth audio signal in theplayback zone produces a sixth audio signal having an audiocharacteristic substantially the same as the predetermined audiocharacteristic, represented by the predetermined audio signal z(t) shownin equations (7) and (8). The computing device may then cause to bestored in the database, an association between the second audioprocessing algorithm and the acoustic characteristic of the secondplayback zone.

While many playback zones may be similar in dimension, buildingmaterial, and/or furniture types and arrangements, it is unlikely thattwo playback zones will have the same exact playback zone acousticcharacteristic. As such, rather than storing an individual entry foreach unique playback zone acoustic characteristic and their respectivecorresponding audio processing algorithms, which may require animpractical amount of memory storage, entries for similar orsubstantially the same playback zone acoustic characteristics may becombined.

In one case, acoustic characteristics of two playback zones may besimilar when the two playback zones are substantially similar rooms. Inanother case, the computing device may, as suggested above, beperforming the method 500 for the same playback device in the sameplayback zone multiple times. In a further case, the computing devicemay be performing method 500 for a different playback device in the sameplayback zone. In yet another case, the computing device may beperforming method 500 for the playback device in the same playback zone,but in a different location within the playback zone. Other examples arealso possible.

Whichever the case, during the process of generating entries of playbackzone acoustic characteristic and corresponding audio processingalgorithms, the computing device may determine that two playback zoneshave substantially the same playback zone acoustic characteristics. Thecomputing device may then responsively determine a third audioprocessing algorithm based on the first audio processing algorithm andthe second audio processing algorithm. For example, the computing devicemay determine the third audio processing algorithm by taking an averageof the parameters of the first and second audio processing algorithms.

The computing device may then store in the database, an associationbetween the third audio processing algorithm and the substantially thesame acoustic characteristics. In one example, the database entry forthe third audio processing algorithm may have a corresponding acousticcharacteristic determined based on an average of the two substantiallythe same acoustic characteristics. In some cases, as suggested above,the database may have only one entry for the substantially the sameacoustic characteristics in the interest of conserving storage memory.As such, the entries for the acoustic characteristics of the firstplayback zone and the second playback zone may be discarded in favor ofthe entry for the third audio processing algorithm. Other examples arealso possible.

While the discussions above generally refer to the method 500 as beingperformed by a computing device, one having ordinary skill in the artwill appreciate that, as indicated above, the functions of method 500may alternatively be performed by one or more other devices, such as oneor more servers, one or more playback devices, and/or one or morecontroller devices. In other words, one or more of the blocks 502-510may be performed by the computing device, while one or more others ofthe blocks 502-510 may be performed by one or more other computingdevices.

In one example, as described above, playback of the first audio signalby the playback device at block 502 may be performed by the playbackdevice without any external command. Alternatively, the playback devicemay play the first audio signal in response to a command from acontroller device and/or another playback device. In another example,blocks 502-506 may be performed by one or more playback devices or oneor more controller devices, and the computing device may perform block508 and 510. In yet another example, blocks 502-508 may be performed byone or more playback devices or one or more controller devices, and thecomputing device may only perform the functions of storing the audioprocessing algorithm at block 510. Other examples are also possible.

b. Example Database of Audio Processing Algorithms and Corresponding Oneor More Characteristics of Playback Zones

As indicated previously, a playback zone may have one or more playbackzone characteristics. The one or more playback zone characteristics mayinclude an acoustic characteristic of the playback zone, as discussedabove. The one or more characteristics of the playback zone may alsoinclude one or more of a (a) a dimension of the playback zone, (b) anaudio reflectivity characteristic of the playback zone (c) an intendeduse of the playback zone, (d) a number of furniture in the playbackzone, (e) size of furniture in the playback zone, and (f) types offurniture in the playback zone. In one case, the audio reflectivitycharacteristic of the playback zone may be related to flooring and/orwall materials of the playback zone.

In some examples, an association between a determined audio processingalgorithm, such as p(t) discussed above, and additional one or morecharacteristics of the playback zone may be stored in the database. FIG.7 shows an example flow diagram of a method 700 for maintaining adatabase of audio processing algorithms and the one or morecharacteristics of the playback zone. Method 700 shown in FIG. 7presents an embodiment of a method that can be implemented within anoperating environment involving, for example, the media playback system100 of FIG. 1, one or more of the playback device 200 of FIG. 2, and oneor more of the control device 300 of FIG. 3. In one example, the method700 may be performed by a computing device that is in communication witha media playback system, such as the media playback system 100. Inanother example, some or all of the functions of method 700 mayalternatively be performed by one or more other computing devices, suchas one or more servers, one or more playback devices, and/or one or morecontroller devices.

Method 700 may include one or more operations, functions, or actions asillustrated by one or more of blocks 702-708. Although the blocks areillustrated in sequential order, these blocks may also be performed inparallel, and/or in a different order than those described herein. Also,the various blocks may be combined into fewer blocks, divided intoadditional blocks, and/or removed based upon the desired implementation.

As shown in FIG. 7, the method 700 involves causing a playback device ina playback zone to play a first audio signal at block 702, receiving (i)data indicating one or more characteristics of a playback zone, and (ii)data indicating a second audio signal detected by a microphone of theplayback device at block 704, based on the second audio signal and acharacteristic of the playback device, determining an audio processingalgorithm at block 706, and causing to be stored in a database, anassociation between the determined audio processing algorithm and atleast one of the one or more characteristics of the playback zone atblock 708.

At block 702, the method 700 involves the computing device causing aplayback device in a playback zone to play a first audio signal. In oneexample, block 702 may include the same, or substantially the samefunctions as that of block 502 described in connection to FIG. 5. Forinstance, the first audio signal may include audio content withfrequencies substantially covering a renderable frequency range of theplayback device or a frequency range audible to a human. As such, anydiscussions above in connection to block 502 may also be application toblock 702.

At block 704, the method 700 involves receiving (i) data indicating oneor more characteristics of the playback zone, and (ii) data indicating asecond audio signal detected by a microphone of the playback device. Inone example, block 704 may include the same, or substantially the samefunctions as that of block 504 described in connection to FIG. 5. Forinstance, the second audio signal may include a portion corresponding tothe first audio signal played by the playback device. As such, anydiscussions above in connection to block 504 may also be applicable toblock 704.

In addition to that described previously in connection to block 504,block 704 also involves receiving data indicating one or morecharacteristics of the playback zone. As indicated above, the playbackzone may be a model playback zone used to simulate a listeningenvironment within which the playback device may play audio content. Insuch a case, some of the one or more playback zone characteristics forthe playback zone may be known. For instance, dimensions, floor plan,construction materials, and furnishings for the playback zone may beknown. In one case, model playback zones may be constructed for thepurposes of determining audio processing algorithms for a database, inwhich case, some of the one or more playback zone characteristics may bepredetermined. In another case, the playback zone may be a room of auser of the playback device. As indicated above, such characteristics ofthe playback zone may contribute to the acoustic characteristic of theplayback zone.

In one example, the computing device may receive the data indicating theone or more playback zone characteristics via a controller interface ofa controller devices used by a user or an acoustics engineer. In anotherexample, the computing device may receive the data indicating the one ormore characteristics of the playback zone from the playback device inthe playback zone. For instance, the data indicating the one or morecharacteristics may be received along with data indicating the secondaudio signal. The data indicating the one or more playback zonecharacteristics may be received before, during, or after playback of thefirst audio signal by the playback device at block 702. Other examplesare also possible.

At block 706, the method 700 involves based on the second audio signaland a characteristic of the playback device, determining an audioprocessing algorithm. In one example, block 706 may include the same orsimilar functions as that described above in blocks 506 and 508 of FIG.5. For instance, determining the audio processing algorithm may involvebased on the second audio signal and a characteristic of the playbackdevice, determining an acoustic characteristic of the playback zone,then based on the acoustic characteristic of the playback zone,determine an audio processing algorithm. The characteristic of theplayback device, as indicated above, may include one or more of anacoustic characteristic of the playback device, specifications of theplayback device, and a model of the playback device.

As discussed previously, application of the determined audio processingalgorithm by the playback device when playing the first audio signal inthe playback zone may produce a third audio signal having an audiocharacteristic substantially the same as a predetermined audiocharacteristic, or assumes the predetermined audio characteristic, atleast to some extent. In one case, the predetermined audiocharacteristic may be the same or substantially the same as thepredetermined audio characteristic represented as the predeterminedaudio signal p(t) discussed above. Other examples are also possible.

At block 708, the method 800 involves causing to be stored in adatabase, an association between the determined audio processingalgorithm and at least one of the one or more characteristics of theplayback zone. In one example, block 708 may include the same or similarfunctions as that described above in blocks 510. In this case however,the computing device may cause to be stored in the database, anassociation between the audio processing algorithm and at least one ofthe one or more characteristics in addition to, or instead of theacoustic characteristic of the playback zone.

As indicated above, the playback zone for which the audio processingalgorithm was determined may be a model playback zone used to simulate alistening environment within which the playback device may play audiocontent, or a room of a user of the playback device. In some cases, thedatabase may include entries generated based on audio signals played anddetected within model playback zones as well as entries generated basedon audio signals played and detected within a room of a user of aplayback device.

FIG. 6B shows an example portion of a database 650 of audio processingalgorithms, within which the audio processing algorithm and associationsbetween the audio processing algorithms and playback zone acousticcharacteristics determined in the discussions above may be stored. Asshown, the portion of the database 650 may include a plurality ofentries 652-658, similar to the entries 602-608 of the database 600. Forinstance, entries 652 and 602 may have the same playback zone acousticcharacteristic, and the same audio processing algorithm coefficients,entries 654 and 604 may have the same playback zone acousticcharacteristic, and the same audio processing algorithm coefficients,entries 656 and 606 may have the same playback zone acousticcharacteristic, and the same audio processing algorithm coefficients,and entries 658 and 608 may have the same playback zone acousticcharacteristic, and the same audio processing algorithm coefficients.

In addition to the playback zone acoustic characteristics, the database650 may also include zone dimensions information, indicating dimensionsof the playback zone having the corresponding playback zone acousticcharacteristic and the audio processing algorithm determined based onthe corresponding playback zone acoustic characteristic. For instance,as shown, the entry 652 may have a zone dimension of a₁×b₁×c₁, the entry654 may have a zone dimension of a₂×b₂×c₂, the entry 656 may have a zonedimension of a₃×b₃×c₃, and the entry 654 may have a zone dimension ofa₄×b₄×c₄. As such, in this example, the one or more characteristicsstored in association with the determined audio processing algorithminclude the acoustic characteristic of the playback zone and dimensionsof the playback zone. Other examples are also possible.

One having ordinary skill in the art will appreciate that database 650is just one example of a database that may be populated and maintainedby performing the functions of method 700. In one example, the playbackzone acoustic characteristics may be stored in a different format ormathematical state (i.e. inversion vs non-inverse functions). In anotherexample, the audio processing algorithms may be stored as functionand/or equalization functions. In yet another example, the database 650may include only zone dimensions and corresponding audio processingalgorithms, and not the corresponding acoustic characteristics of theplayback zone. Other examples are also possible.

Similar to method 500, the method 700 as described above (or somevariation of the method 700) may further be performed to generate otherentries in the database. For instance, given that the playback device isa first playback device, the playback zone is a first playback zone, andthe audio processing algorithm is a first audio processing algorithm,the method 600 may additionally or alternatively be performed using asecond playback device in a second playback zone. In one example, thesecond playback device may play a fourth audio signal in the secondplayback zone and a microphone of the second playback device may detecta fifth audio signal that includes a portion of the fourth audio signalplayed by the second playback device. The computing device may thenreceive (i) data indicating one or more characteristics of the secondplayback zone, and (ii) data indicating the fifth audio signal detectedby a microphone of a second playback device in the second playback zone.

The computing device may then determine an acoustic characteristic ofthe second playback zone based on the fifth audio signal and acharacteristic of the second playback device. Based on the acousticcharacteristic of the second playback zone, the computing device maydetermine a second audio processing algorithm such that applying of thedetermined second audio processing algorithm by the second playbackdevice when playing the fourth audio signal in the playback zoneproduces a sixth audio signal having an audio characteristicsubstantially the same as the predetermined audio characteristic,represented by the predetermined audio signal z(t) shown in equations(7) and (8). The computing device may then cause to be stored in adatabase, an association between the second audio processing algorithmand at least one of the one or more characteristics of the secondplayback zone.

Similar to that discussed above in connection to the method 500, duringthe process of generating entries for the database, the computing devicemay determine that two playback zones have similar or substantially thesame playback zone acoustic characteristics. Accordingly, as alsodiscussed above, the computing device may combine the playback zoneacoustic characteristics and determined audio processing algorithmscorresponding to the playback zone acoustic characteristics (i.e. byaveraging), and store the combined playback zone acoustic characteristicand combined audio processing algorithm as a single entry in thedatabase. Other examples are also possible.

Similar to the case of method 500, while the discussions above generallyrefer to the method 700 as being performed by a computing device, onehaving ordinary skill in the art will appreciate that the functions ofmethod 700 may alternatively be performed by one or more other computingdevices, such as one or more servers, one or more playback devices,and/or one or more controller devices. In other words, one or more ofthe blocks 702-708 may be performed by the computing device, while oneor more others of the blocks 702-708 may be performed by one or moreother computing devices. The other computing devices may include one ormore playback devices, one or more controller devices, and/or one ormore servers.

In one example, as described above, playback of the first audio signalby the playback device at block 702 may be performed by the playbackdevice without any external command. Alternatively, the playback devicemay play the first audio signal in response to a command from acontroller device and/or another playback device. In another example,blocks 702-706 may be performed by one or more playback devices or oneor more controller devices, and the computing device may perform block708. Other examples are also possible.

IV. Calibrating a Playback Device Based on Playback Zone Characteristics

As indicated above, some examples described herein involve calibrating aplayback device for a playback zone. In some cases, calibration of theplayback deice may involve determining an audio processing algorithm forthe playback device to apply when playing audio content in the playbackzone.

FIG. 8 shows an example playback environment 800 within which a playbackdevice may be calibrated. As shown, the playback environment 800includes a computing device 802, playback devices 804 and 806,controller device 808, and a playback zone 810. Playback devices 804 and806 may be similar to the playback device 200 shown in FIG. 2. As such,playback devices 804 and 806 may each have a microphone, such as themicrophone 220. In some cases, only one of the playback devices 804 and806 may have a microphone.

In one example, playback devices 804 and 806 may be part of a mediaplayback system and may be configured to play audio content insynchrony, such as that shown and discussed above in connection to themedia playback system 100 of FIG. 1. In one case, playback devices 804and 806 may be grouped together to play audio content in synchronywithin the playback zone 810. Referring again to FIG. 1, the playbackzone 810 may be any one or more of the different rooms and zone groupsin the media playback system 100. For instance, the playback zone 810may be the master bedroom. In such a case, the playback devices 804 and806 may correspond to the playback devices 122 and 124, respectively.

In one example, the controller device 808 may be a device that can beused to control the media playback system. In one case, the controllerdevice 808 may be similar to the control device 300 of FIG. 3. While thecontroller device 808 of FIG. 8 is shown to be inside the playback zone810, the controller device 808 may be outside of the playback zone 810,or moving in or out of the playback zone 810 while communicating withthe playback device 804, the playback device 806, and or any otherdevice in the media playback system.

In one example, the computing device 802 may be a server incommunication with the media playback system. The computing device 802may be configured to maintain a database of information associated withthe media playback system, such as registration numbers associated withthe playback devices 804 and 806. The computing device 802 may also beconfigured to maintain a database of audio processing algorithms, asdescribed in the previous section. Other examples are also possible.

Methods 900, 1000, and 1100, as will be discussed below providefunctions that may be performed for calibration of a playback device ina playback zone, such as the playback devices 804 and 806 in theplayback zone 810.

a. First Example Method for Determining an Audio Processing AlgorithmBased on a Detected Audio Signal

FIG. 9 shows an example flow diagram of a method 900 for determining anaudio processing algorithm based on one or more playback zonecharacteristics. Method 900 shown in FIG. 9 presents an embodiment of amethod that can be implemented within an operating environmentinvolving, for example, the media playback system 100 of FIG. 1, one ormore of the playback device 200 of FIG. 2, one or more of the controldevice 300 of FIG. 3, and the playback environment 800 of FIG. 8. In oneexample, the method 900 may be performed by a computing device incommunication with a media playback system. In another example, some orall of the functions of method 900 may alternatively be performed by oneor more other computing devices, such as one or more servers, one ormore playback devices, and/or one or more controller devices associatedwith the media playback system.

Method 900 may include one or more operations, functions, or actions asillustrated by one or more of blocks 902-908. Although the blocks areillustrated in sequential order, these blocks may also be performed inparallel, and/or in a different order than those described herein. Also,the various blocks may be combined into fewer blocks, divided intoadditional blocks, and/or removed based upon the desired implementation.

As shown in FIG. 9, the method 900 involves a causing a playback devicein a playback zone to play a first audio signal at block 902, receivingfrom the playback device, data indicating a second audio signal detectedby a microphone of the playback device at block 904, based on the secondaudio signal and an acoustic characteristic of the playback device,determining an audio processing algorithm at block 906, and transmittingdata indicating the determined audio processing algorithm to theplayback device at block 908.

At block 902, the method 900 involves causing a playback device in aplayback zone to play a first audio signal. Referencing FIG. 8, theplayback device may be the playback device 804, and the playback zonemay be the playback zone 810. As such, the playback device may be aplayback device similar to the playback device 200 shown in FIG. 2.

In one example, the computing device 802 may determine that the playbackdevice 804 is to be calibrated for the playback zone 810, andresponsively cause the playback device 804 in the playback zone 810 toplay the first audio signal. In one case, the computing device 802 maydetermine that the playback device 804 is to be calibrated based on aninput received from a user indicating that the playback device 804 is tobe calibrated. In one instance, the input may be received from the uservia the controller device 808. In another case, the computing device 802may determine that the playback device 804 is to be calibrated becausethe playback device 804 is a new playback device, or newly moved to theplayback zone 810. In a further case, calibration of the playback device804 (or any other playback devices in the media playback system) may beperformed periodically. As such, the computing device 802 may determinethat the playback device 804 is to be calibrated based on a calibrationschedule of the playback device 804. Other examples are also possible.Responsive to determining that the playback device 804 is to becalibrated, the computing device 802 may then cause the playback device804 to play the first audio signal.

While block 902 involves the computing device 802 causing the playbackdevice 804 to play the first audio signal, one having ordinary skill inthe art will appreciate that playback of the first audio signal by theplayback device 804 may not necessarily be caused or initiated by thecomputing device 802. For instance, the controller device 808 may send acommand to the playback device 804 to cause the playback device 804 toplay the first audio signal. In another instance, the playback device806 may cause the playback device 804 to play the first audio signal. Ina further instance, the playback device 804 may play the first audiosignal without receiving a command from the computing device 802,playback device 806, or controller device 808. In one example, theplayback device 804 may determine, based on a movement of the playbackdevice 804, or a change in the playback zone of the playback device 804,that a calibration is to be performed, and responsive play the firstaudio signal. Other examples are also possible.

As suggested, the first audio signal may be a test signal or measurementsignal for calibrating the playback device 804 for the playback one 810.As such, the first audio signal may be representative of audio contentthat may be played by the playback device during regular use by a user.Accordingly, the first audio signal may include audio content withfrequencies substantially covering a renderable frequency range of theplayback device or a frequency range audible to a human. In anotherexample, the first audio signal may be a favorite or commonly playedaudio track of a user of the playback device.

At block 904, the method 900 involves receiving from the playbackdevice, a second audio signal detected by a microphone of the playbackdevice. Continuing with the examples above, given the playback device804 is similar to the playback device 200 of FIG. 2, the microphone ofthe playback device 804 may be similar to the microphone 220 of theplayback device 200. In one example, the computing device 802 mayreceive the data from the playback device 804. In another example, thecomputing device 804 may receive the data via another playback devicesuch as the playback device 806, a controller device such as thecontroller device 808, or another computing device, such as anotherserver.

While the playback device 804 is playing the first audio signal, orshortly thereafter, the microphone of the playback device 804 may detectthe second audio signal. The second audio signal may include soundspresent in the playback zone. For instance, the second audio signal mayinclude a portion corresponding to the first audio signal played by theplayback device 804.

In one example, the computing device 802 may receive data indicating thefirst audio signal from the playback device 804 as a media stream whilethe microphone detects the second audio signal. In another example, thecomputing device 802 may receive from the playback device 804, dataindicating the second audio signal once detection of the second audiosignal by the microphone of the playback device 804 is complete. Ineither case, the playback device 804 may process the detected secondaudio signal (via an audio processing component, such as the audioprocessing component 208 of the playback device 200) to generate thedata indicating the second audio signal, and transmit the data to thecomputing device 802. In one instance, generating the data indicatingthe second audio signal may involve converting the second audio signalfrom an analog signal to a digital signal. Other examples are alsopossible.

At block 906, the method 900 involves based on the second audio signaland an acoustic characteristic of the playback device, determining anaudio processing algorithm. In one example, the acoustic characteristicof the playback device may be h_(p)(t) as discussed above in connectionto block 506 of the method 500 shown in FIG. 5. For instance, asdescribed above, the acoustic characteristic of the playback device maybe determined by causing a reference playback device in an anechoicchamber to play a measurement signal, receiving from the referenceplayback device, data indicating an audio signal detected by amicrophone of the reference playback device, and determining theacoustic characteristic of the playback device based on comparisonbetween detected audio signal and the measurement signal.

As suggested above, the reference playback device may be of the samemodel as the playback device 804 being calibrated for the playback zone810. Also similar to that discussed above in connection to block 506,the computing device may accordingly determine an acousticcharacteristic of the playback zone based on the acoustic characteristicof the playback device and the second audio signal.

In one example, the computing device 802 may determine an audioprocessing algorithm based on the acoustic characteristic of theplayback zone similar to that discussed above in connection to block508. As such, the computing device 802 may determine the audioprocessing algorithm based on the acoustic characteristic of theplayback zone and a predetermined audio characteristic, such that anapplication of the determined audio processing algorithm by the playbackdevice 804 when playing the first audio signal in the playback zone 810may produce a third audio signal having an audio characteristicsubstantially the same as the predetermined audio characteristic, orassumes the predetermined audio characteristic, at least to some extent.

In another example, the computing device 802 may select from a pluralityof audio processing algorithms, an audio processing algorithmcorresponding to the acoustic characteristic of the playback zone 810.For instance, the computing device may access a database, such as thedatabases 600 and 650 of FIGS. 6A and 6B, respectively, and identify anaudio processing algorithm based on the acoustic characteristic of theplayback zone 810. For instance, referring to the database 600 of FIG.6A, if the acoustic characteristic of the playback zone 810 isdetermined as h_(room) ⁻¹(t)−3, then the audio processing algorithmhaving coefficients w₃, x₃, y₃, and z₃ of database entry 606 may beidentified.

In some cases, an acoustic characteristic that exactly matches thedetermined acoustic characteristic of the playback zone 810 may not befound in the database. In such a case, an audio processing algorithmcorresponding to an acoustic characteristic in the database that is themost similar to the acoustic characteristic of the playback zone 810 maybe identified. Other examples are also possible.

At block 908, the method 900 involves transmitting data indicating thedetermined audio processing algorithm to the playback device. Continuingwith the examples above, the computing device 802 (or one or more otherdevices) may transmit the data indicating the determined audioprocessing algorithm to the playback device 804. The data indicating thedetermined audio processing algorithm may also include a command tocause the playback device 804 to apply the determined audio processingalgorithm when playing audio content in the playback zone 810. In oneexample, applying the audio processing algorithm to the audio contentmay modify a frequency equalization of the audio content. In anotherexample, applying the audio processing algorithm to the audio contentmay modify a volume range of the audio content. Other examples are alsopossible.

In some cases, a playback zone may include multiple playback devicesconfigured to play audio content in synchrony. For instance, asindicated above, playback devices 804 and 806 may be configured to playaudio content in synchrony in the playback zone 810. In such a case,calibration of one of the playback devices may involve the otherplayback devices.

In one example, a playback zone such as the playback zone 810 mayinclude a first playback device, such as the playback device 804, and asecond playback device, such as the playback device 806, configured toplay audio content in synchrony. Calibration of the playback device 804,as coordinated and performed by the computing device 802, may involvecausing the playback device 804 to play a first audio signal and causingthe playback device 806 to play a second audio signal.

In one case, the computing device 802 may cause the playback device 806to play the second audio signal in synchrony with playback of the firstaudio signal by the playback device 804. In one instance, the secondaudio signal may be orthogonal to the first audio signal such that acomponent of the synchronously played audio content played by either ofthe playback devices 804 and 806 may be discernable. In another case,the computing device may cause the playback device 806 to play thesecond audio signal after playback of the first audio signal by theplayback device 804 is complete. Other examples are also possible.

The computing device 802 may then receive from the playback device 804,a third audio signal detected by a microphone of the playback device804, similar to that discussed in connection to block 904. In this casehowever, the third audio signal may include both a portion correspondingto the first audio signal played by the playback device 804, and aportion corresponding to the second audio signal played by playbackdevice 806.

Based on the third audio signal and an acoustic characteristic of theplayback device 804, the computing device 802 may then determine anaudio processing algorithm, and transmit data indicating the determinedaudio processing algorithm to the playback device 804 for the playbackdevice 804 to apply when playing audio content in the playback zone 810,similar to that described above in connection to blocks 906 and 908.

In one case, as indicated above, the playback device 806 may also have amicrophone and may also be calibrated similarly to that described above.As indicated, the first audio signal played by the playback device 804and the second audio signal played by the playback device 806 may beorthogonal, or otherwise discernable. For instance, as also indicatedabove, the playback device 806 may play the second audio signal afterplayback of the first audio signal by the playback device 804 iscompleted. In another instance, the second audio signal may have a phasethat is orthogonal to a phase of the first audio signal. In yet anotherinstance, the second audio signal may have a different and/or varyingfrequency range than the first audio signal. Other examples are alsopossible.

Whichever the case, discernable first and second audio signals may allowthe computing device 802 to parse from the third audio signal detectedby the playback device 804, a contribution of the playback device 804 tothe detected third audio signal, and a contribution of the playbackdevice 806 to the detected third audio signal. Respective audioprocessing algorithms may then be determined for the playback device 804and the playback device 806.

The respective audio processing algorithms may be determined similar tothat discussed above in connection to block 508. In one case, a firstacoustic characteristic of the playback zone may be determined based onthe third audio signal detected by the playback device 604, and a secondacoustic characteristic of the playback zone may be determined based ona fourth audio signal detected by the playback device 806. Similar tothe third audio signal, the fourth audio signal may also include aportion corresponding to the first audio signal played by the playbackdevice 804 and a portion corresponding to the second audio signal playedby the playback device 806.

Respective audio processing algorithms for the playback device 804 andthe playback device 806 may then be determined based on the firstacoustic characteristic of the playback zone and the second acousticcharacteristic of the playback zone either individually or incombination. In some instances, a combination of the first acousticcharacteristic of the playback zone and the second acousticcharacteristic of the playback zone may represent a more comprehensiveacoustic characteristic of the playback zone than either the first orsecond acoustic characteristic of the playback zone individually. Therespective audio processing algorithms may then be transmitted to theplayback device 804 and the playback device 806 to apply when playingaudio content in the playback zone 810. Other examples are alsopossible.

While the discussions above generally refer to the method 900 as beingperformed by the computing device 802 of FIG. 8, one having ordinaryskill in the art will appreciate that, as indicated above, the functionsof method 900 may alternatively be performed by one or more othercomputing devices, such as one or more servers, one or more playbackdevices, and/or one or more controller devices. For instance, thefunctions of method 900 to calibrate the playback device 804 for theplayback zone 810 may be performed by the playback device 804, theplayback device 806, the controller device 808, or another device incommunication with the playback device 804, but not shown in FIG. 8.

Further, in some cases, one or more of the blocks 902-908 may beperformed by the computing device 802, while one or more others of theblocks 902-908 may be performed by one or more other devices. Forinstance, blocks 902 and 904 may be performed by one or more of theplayback device 804, the playback device 806, and the playback device808. In other words, a coordinating device other than the computingdevice 802 may coordinate calibration of the playback device 804 for theplayback zone 810.

In some cases, at block 906, the coordinating device may transmit thesecond audio signal to the computing device 802 such that the computingdevice 802 may determine the audio processing algorithm based on thesecond audio signal and the acoustic characteristic of the playbackdevice. The acoustic characteristic of the playback device may beprovided to the computing device 802 by the coordinating device, orprovided from another device on which characteristics of the playbackdevice is stored. In one case, the computing device 802 may perform thecalculations of block 906 because the computing device 802 has moreprocessing power than the coordinating device.

In one example, upon determining the audio processing algorithm, thecomputing device 802 may transmit the determined audio processingalgorithm directly to the playback device 804 for the playback device804 to apply when playing audio content in the playback zone 810. Inanother example, upon determining the audio processing algorithm, thecomputing device 802 may transmit the determined audio processingalgorithm to the coordinating device, and the coordinating device mayperform block 908 and transmit the determined processing algorithm tothe playback device 804 (if the coordinating device is not also theplayback device 804). Other examples are also possible.

b. Second Example Methods for Determining an Audio Processing AlgorithmBased on a Detected Audio Signal

In some cases, as described above, calibration of a playback device in aplayback zone may be coordinated and performed by a computing devicesuch as a server, or a controller device. In some other cases, as alsodescribed above, calibration of a playback device may be coordinatedand/or performed by the playback device being calibrated.

FIG. 10 shows an example flow diagram of a method 1000 for determiningan audio processing algorithm based on one or more playback zonecharacteristics, as performed by the playback device being calibrated.Method 1000 shown in FIG. 10 presents an embodiment of a method that canbe implemented within an operating environment involving, for example,the media playback system 100 of FIG. 1, one or more of the playbackdevice 200 of FIG. 2, one or more of the control device 300 of FIG. 3,and the playback environment 800 of FIG. 8. As indicated, method 800 maybe performed by the playback device to be calibrated for a playbackzone. In some cases, some of the functions of method 1000 mayalternatively be performed by one or more other computing devices, suchas one or more servers, one or more other playback devices, and/or oneor more controller devices.

Method 1000 may include one or more operations, functions, or actions asillustrated by one or more of blocks 1002-1008. Although the blocks areillustrated in sequential order, these blocks may also be performed inparallel, and/or in a different order than those described herein. Also,the various blocks may be combined into fewer blocks, divided intoadditional blocks, and/or removed based upon the desired implementation.

As shown in FIG. 10, the method 1000 involves while in a playback zone,playing a first audio signal at block 1002, detecting by a microphone, asecond audio signal at block 1004, based on the second audio signal andan acoustic characteristic of the playback device, determining an audioprocessing algorithm at block 1006, and applying the determined audioprocessing algorithm to audio data corresponding to a media item whenplaying the media item at block 1008.

At block 1002, the method 1000 involves while in a playback zone,playing a first audio signal. Referring to FIG. 8, the playback deviceperforming method 1000 may be the playback device 804, while theplayback device 804 is in the playback zone 810. In one example, block1002 may be similar to block 902, but performed by the playback device804 being calibrated rather than the computing device 802. Nevertheless,any discussions above in connection to block 902 may also be applicable,sometimes with some variation, to block 1002.

At block 1004, the method 1000 involves detecting by a microphone, asecond audio signal. The second audio signal may include a portioncorresponding to the first audio signal played by the playback device.In one example, block 1004 may be similar to block 904, but performed bythe playback device 804 being calibrated rather than the computingdevice 802. Nevertheless, any discussions above in connection to block904 may also be applicable, sometimes with some variation, to block1004.

At block 1006, the method 1000 involves based on the second audio signaland an acoustic characteristic of the playback device, determining anaudio processing algorithm. In one example, block 1006 may be similar toblock 906, but performed by the playback device 804 being calibratedrather than the computing device 802. Nevertheless, any discussionsabove in connection to block 906 may also be applicable, sometimes withsome variation, to block 1006.

In one case, functions for determining the audio processing algorithm,as discussed in connection to block 906, may be performed wholly by theplayback device 804 that is being calibrated for the playback zone 810.As such, the playback device 804 may determine an acousticcharacteristic of the playback zone 610 based on the second audio signaland an acoustic characteristic of the playback device 804. In one case,the playback device 804 may have stored locally, the acousticcharacteristic of the playback device 804. In another case, the playbackdevice 804 may receive from another device, the acoustic characteristicof the playback device 804.

In one example, the playback device 804 may then select from a pluralityof audio processing algorithms, an audio processing algorithmcorresponding to the acoustic characteristic of the playback zone 610.For instance, the playback device 804 may access a database such thedatabases 600 and 650 shown in and described above in connection toFIGS. 6A and 6B, respectively, and identify in the database an audioprocessing algorithm corresponding to an acoustic characteristicsubstantially similar to the acoustic characteristic of the playbackzone 610.

In another example, similar to functions described above in connectionto block 906 of the method 900 and/or block 508 of the method 500, theplayback device 804 may calculate the audio processing algorithm basedon the acoustic characteristics of the playback zone 610 and apredetermined audio characteristic, such that an application of thedetermined audio processing algorithm by the playback device 804 whenplaying the first audio signal in the playback zone 810 may produce athird audio signal having an audio characteristic substantially the sameas the predetermined audio characteristic, or assumes the predeterminedaudio characteristic, at least to some extent.

In a further example, as discussed in previous section, another deviceother than the playback device 804 may perform some or all of thefunctions of block 1006. For instance, the playback device 804 maytransmit data indicating the detected second audio signal to a computingdevice, such as the computing device 802, another playback device suchas the playback device 806, a controller device such as the controllerdevice 808, and/or some other device in communication with the playbackdevice 804, and request an audio processing algorithm. In anotherinstance, the playback device 804 may determine the acousticcharacteristic of the playback zone 810 based on the detected audiosignal, and transmit data indicating the determined acousticcharacteristic of the playback zone 810 to the other device with arequest for an audio processing algorithm based on the determinedacoustic characteristic of the playback zone 810.

In other words, in one aspect, the playback device 804 may determine theaudio processing algorithm by requesting from the other device, an audioprocessing algorithm based on the detected second audio signal and/oracoustic characteristic of the playback zone 810 provided to the otherdevice by the playback device 804

In a case where the playback device 804 provides data indicating thedetected second audio signal but not the acoustic characteristic of theplayback zone 810, the playback device 804 may also transmit theacoustic characteristic of the playback device 804 along with the dataindicating the detected second audio signal such that the other devicemay determine the acoustic characteristic of the playback zone 810. Inanother case, the device receiving the data indicating the detectedsecond audio signal may determine based on the data, a model of theplayback device 804 transmitting the data, and determine an acousticcharacteristic of the playback device 804 based on the model of theplayback device 804 (i.e. a playback device acoustic characteristicdatabase). Other examples are also possible.

The playback device 804 may then receive the determined audio processingalgorithm. In one case, the playback device 804 may send the secondaudio signal to the other device because the other device has moreprocessing power than the playback device 804. In another case, theplayback device 804 and one or more other devices may perform thecalculations and functions in parallel for an efficient use ofprocessing power. Other examples are also possible.

At block 1008, the method 800 involves applying the determined audioprocessing algorithm to audio data corresponding to a media item whenplaying the media item. In one example, application of the audioprocessing algorithm to the audio data of the media item by the playbackdevice 804 when playing the media item in the playback zone 810 maymodify a frequency equalization of the media item. In another example,application of the audio processing algorithm to the audio data of themedia item by the playback device 804 when playing the media item in theplayback zone 810 may modify a volume range of the media item. In oneexample, the playback device 804 may store in local memory storage, thedetermined audio processing algorithm and apply the audio processingalgorithm when playing audio content in the playback zone 810.

In one example, the playback device 804 may be calibrated for differentconfigurations of the playback device 804. For instance, the playbackdevice 804 may be calibrated for a first configuration involvingindividual playback in the playback zone 810, as well as for a secondconfiguration involving synchronous playback with the playback device806 in the playback zone 810. In such a case, a first audio processingalgorithm determined, stored, and applied for the first playbackconfiguration of the playback device, and a second audio processingalgorithm determined, stored, and applied for the second playbackconfiguration of the playback device.

The playback device 804 may then determine based on a playbackconfiguration the playback device 804 is in at a given time, which audioprocessing algorithm to apply when playing audio content in the playbackzone 810. For instance, if the playback device 804 is playing audiocontent in the playback zone 810 without the playback device 806, theplayback device 804 may apply the first audio processing algorithm. Onthe other hand, if the playback device 804 is playing audio content inthe playback zone 810 in synchrony with the playback device 806, theplayback device 804 may apply the second audio processing algorithm.Other examples are also possible.

c. Example Method for Determining an Audio Processing Algorithm Based onPlayback Zone Characteristics

In the discussions above, determination of an audio processing algorithmmay be generally based on determining an acoustic characteristic of theplayback zone, as determined based on an audio signal detected by aplayback device in the playback zone. In some cases, an audio processingalgorithm may also be identified based on other characteristics of theplayback zone, in addition to or instead of the acoustic characteristicof the playback zone.

FIG. 11 shows an example flow diagram for providing an audio processingalgorithm from a database of audio processing algorithms based on one ormore characteristics of the playback zone. Method 1100 shown in FIG. 11presents an embodiment of a method that can be implemented within anoperating environment involving, for example, the media playback system100 of FIG. 1, one or more of the playback device 200 of FIG. 2, one ormore of the control device 300 of FIG. 3, and the playback environment800 of FIG. 8. In one example, method 1100 may be performed, eitherindividually or collectively by one or more playback devices, one ormore controller devices, one or more servers, or one or more computingdevices in communication with the playback device to be calibrated forthe playback zone.

Method 1100 may include one or more operations, functions, or actions asillustrated by one or more of blocks 1102-1108. Although the blocks areillustrated in sequential order, these blocks may also be performed inparallel, and/or in a different order than those described herein. Also,the various blocks may be combined into fewer blocks, divided intoadditional blocks, and/or removed based upon the desired implementation.

As shown in FIG. 11, the method 1100 involves maintaining a database of(i) a plurality of audio processing algorithms and (ii) a plurality ofplayback zone characteristics at block 1102, receiving data indicatingone or more characteristics of a playback zone at block 1104, based onthe data, identifying in the database, and audio processing algorithm atblock 1106, and transmitting data indicating the identified audioprocessing algorithm at block 1108.

At block 1102, the method 1100 involves maintaining a database of (i) aplurality of audio processing algorithms and (ii) a plurality ofplayback zone characteristics. In one example, the database may besimilar to the databases 600 and 650 as shown in and described above inconnection to FIGS. 6A and 6B, respectively. As such, each audioprocessing algorithm of the plurality of audio processing algorithms maycorrespond to one or more playback zone characteristics of the pluralityof playback zone characteristics. Maintenance of the database may be asdescribed above in connection to the methods 500 and 700 of FIGS. 5 and7, respectively. As discussed above, the database may or may not bestored locally on the device maintaining the database.

At block 1104, the method 1100 involves receiving data indicating one ormore characteristics of a playback zone. In one example, the one or morecharacteristics of the playback zone may include an acousticcharacteristic of the playback zone. In another example, the one or morecharacteristics of the playback zone may include a dimension of theplayback zone, a flooring material of the playback zone, a wall materialof the playback zone, an intended use of the playback zone, an number offurniture in the playback zone, a size of furniture in the playbackzone, and types of furniture in the playback zone, among otherpossibilities.

In one example, referring again to FIG. 8, playback device 804 may becalibrated for the playback zone 810. As indicated above, method 1100may be performed, either individually or collectively by the playbackdevice 804 being calibrated, the playback device 806, the controllerdevice 808, the computing device 802, or another device in communicationwith the playback device 804.

In one case, the one or more characteristics may include an acousticcharacteristic of the playback zone 810. In such a case, the playbackdevice 804 in the playback zone 810 may play a first audio signal anddetect by a microphone of the playback device 804, a second audio signalthat includes a portion corresponding to the first audio signal. In oneinstance, the data indicating the one or more characteristics may bedata indicating the detected second audio signal. In another instance,based on the detected second audio signal and an acoustic characteristicof the playback device 804, the acoustic characteristic of the playbackzone 810 may be determined, similar to that discussed previously. Thedata indicating the one or more characteristics may then indicate theacoustic characteristic of the playback zone. In either instance, dataindicating the one or more characteristics may then be received by atleast one of the one or more devices performing the method 1100.

In another case, the one or more characteristics may include a dimensionof the playback zone, a flooring material of the playback zone, and awall material of the playback zone etc. In such a case, a user may beprompted via a controller interface provided by a controller device suchas the controller device 808, to enter or select one or morecharacteristics of the playback zone 810. For instance, the controllerinterface may provide a list of playback zone dimensions, and/or a listof furniture arrangements, among other possibilities for the user toselect from. The data indicating the one or more characteristics of theplayback zone 810, as provided by the user, may then be received by atleast one of the one or more devices performing the method 1100.

At block 1106, the method 1100 involves based on the data, identifyingin the database, an audio processing algorithm. Referring to the casewhere the one or more characteristics include the acousticcharacteristic of the playback zone 810, an audio processing algorithmmay be identified in the database based on the acoustic characteristicsof the playback zone 810. For instance, referring to the database 600 ofFIG. 6A, if the received data indicates an acoustic characteristic ofthe playback zone 810 as h_(room) ⁻¹(t)−3, or substantially the same ash_(room) ⁻¹(t)−3, then the audio processing algorithm of database entry606 having coefficients w₃, x₃, y₃, and z₃ may be identified. In theinstance the data indicating the one or more characteristics of theplayback zone simply includes data indicating the detected second audiosignal, the acoustic characteristic of the playback zone may further bedetermined as described previously, prior to identifying the audioprocessing algorithm. Other examples are also possible.

Referring to a case where the one or more characteristics includedimensions of the playback zone, among other characteristics, an audioprocessing algorithm may be identified in the database based on thedimensions of the playback zone. For instance, referring to the database650 of FIG. 6B, if the received data indicates dimensions of theplayback zone 810 as a₄×b₄×c₄, or substantially the same as a₄×b₄×c₄,then the audio processing algorithm of database entry 658 havingcoefficients w₄, x₄, y₄, and z₄ may be identified. Other examples arealso possible.

In some cases, more than one audio processing algorithm may beidentified based on the one or more characteristics of the playback zoneindicated in the received data. For instance, the acousticcharacteristic of the playback zone 810 may be determined as h_(room)⁻¹(t)−3, which corresponds to audio processing algorithm parameters w₃,x₃, y₃, and z₃, as provided in entry 656 of the database 650 of FIG. 6,while the dimensions provided by the user for the playback zone 810 maybe a₄×b₄×c₄, which corresponds to audio processing algorithm parametersw₄, x₄, y₄, and z₄, as provided in entry 658.

In one example, the audio processing algorithm corresponding to amatching or substantially matching acoustic characteristic may beprioritized. In another example, an average of the audio processingalgorithms (i.e. an averaging of the parameters) may be calculated, andthe average audio processing algorithm may be the identified audioprocessing algorithm. Other examples are also possible.

At block 1108, the method 1100 involves transmitting data indicating theidentified audio processing algorithm. Continuing with the examplesabove, the data indicating the identified audio processing algorithm maybe transmitted to the playback device 804 being calibrated for theplayback zone 810. In one case, the data indicating the identified audioprocessing algorithm may be transmitted directly to the playback device804. In another case, such as if the calibration of the playback device804 is coordinated by the controller device 808, and if the audioprocessing algorithm was identified by the computing device 802, thedata indicating the identified audio processing algorithm may betransmitted to the playback device 804 from the computing device 802 viathe controller device 808. Other examples are also possible.

As indicated above, the functions of method 1100 may be performed by oneor more of one or more servers, one or more playback devices, and/or oneor more controller devices. In one example, maintenance of the databaseat block 1102 may be performed by the computing device 802, andreceiving of data indicating the one or more characteristics of theplayback zone at block 1104 may be performed by the controller device808 (the data may be provided to the controller device 808 by theplayback device 804 being calibrated in the playback zone 810). Block1106 may be performed by the controller device 808 communicating withthe computing device 802 to access the database maintained by thecomputing device 802 to identify the audio signal processing, and block1108 may involve the computing device 802 transmitting the dataindicating the identified audio processing algorithm to the playbackdevice 804 either directly or via the controller device 808.

In another example, the functions of method 1100 may be performed whollyor substantially wholly by one device. For instance, the computingdevice 802 may maintain the database as discussed in connection to block1102.

The computing device 802 may then coordinate calibration of the playbackdevice 804. For instance, the computing device 802 may cause theplayback device 804 to play a first audio signal and detect a secondaudio signal, receive from the playback device 804 data indicating thedetected second audio signal, and determine an acoustic characteristicof the playback zone 810 based on the data from the playback device 804.In another instance, the computing device 802 may cause the controllerdevice 808 to prompt a user to provide one or more characteristics ofthe playback zone 810 (i.e. dimensions etc., as discussed above) andreceive data indicating the user-provided characteristics of theplayback zone 810.

The computing device may then, at block 1106 identify an audioprocessing algorithm based on the received data, and at block 1108,transmit data indicating the identified audio processing algorithm tothe playback device 804. The computing device 802 may also transmit acommand for the playback device 804 to apply the identified audioprocessing algorithm when playing audio content in the playback zone810. Other examples are also possible.

V. Conclusion

The description above discloses, among other things, various examplesystems, methods, apparatus, and articles of manufacture including,among other components, firmware and/or software executed on hardware.It is understood that such examples are merely illustrative and shouldnot be considered as limiting. For example, it is contemplated that anyor all of the firmware, hardware, and/or software aspects or componentscan be embodied exclusively in hardware, exclusively in software,exclusively in firmware, or in any combination of hardware, software,and/or firmware. Accordingly, the examples provided are not the onlyway(s) to implement such systems, methods, apparatus, and/or articles ofmanufacture.

Additionally, references herein to “embodiment” means that a particularfeature, structure, or characteristic described in connection with theembodiment can be included in at least one example embodiment of aninvention. The appearances of this phrase in various places in thespecification are not necessarily all referring to the same embodiment,nor are separate or alternative embodiments mutually exclusive of otherembodiments. As such, the embodiments described herein, explicitly andimplicitly understood by one skilled in the art, can be combined withother embodiments.

The specification is presented largely in terms of illustrativeenvironments, systems, procedures, steps, logic blocks, processing, andother symbolic representations that directly or indirectly resemble theoperations of data processing devices coupled to networks. These processdescriptions and representations are typically used by those skilled inthe art to most effectively convey the substance of their work to othersskilled in the art. Numerous specific details are set forth to provide athorough understanding of the present disclosure. However, it isunderstood to those skilled in the art that certain embodiments of thepresent disclosure can be practiced without certain, specific details.In other instances, well known methods, procedures, components, andcircuitry have not been described in detail to avoid unnecessarilyobscuring aspects of the embodiments. Accordingly, the scope of thepresent disclosure is defined by the appended claims rather than theforgoing description of embodiments.

When any of the appended claims are read to cover a purely softwareand/or firmware implementation, at least one of the elements in at leastone example is hereby expressly defined to include a tangible,non-transitory medium such as a memory, DVD, CD, Blu-ray, and so on,storing the software and/or firmware.

1. A method to be performed by a computing system, the methodcomprising: calibrating a playback device, wherein calibrating theplayback device comprises: determining that the playback device is in aparticular type of zone; querying a database of pre-determinedcalibrations for a particular pre-determined calibration, the particularpre-determined calibration offsetting acoustic characteristics of amodel zone that simulates the particular type of zone, wherein the modelzone is based on additional zones corresponding to the particular typeof zone, and wherein the database is hosted by one or more serversremote from the playback device; and causing, via a network interface,the playback device to apply the particular pre-determined calibrationto the playback device; and causing, via the network interface, theplayback device to play back audio while the particular pre-determinedcalibration is applied to the playback device.
 2. The method of claim 1,wherein determining that the playback device is in the particular typeof zone comprises: receiving audio data recorded via a microphone whilethe playback device played back audio, and determining that the playbackdevice is in the particular type of zone based on the received audiodata.
 3. The method of claim 1, wherein determining that the playbackdevice is in the particular type of zone comprises receiving, via thenetwork interface from a control device, data representing theparticular type of zone, wherein the data is based on user input at thecontrol device indicating the particular type of zone.
 4. The method ofclaim 1, wherein determining that the playback device is in theparticular type of zone comprises accessing, from data storage, a modelof the playback device, wherein playback devices of that model areconfigured to be positioned in the particular type of zone; and whereinquerying the database of pre-determined calibrations for the particularpre-determined calibration comprises querying the database using themodel of the playback device to retrieve the particular pre-determinedcalibration.
 5. The method of claim 1, wherein the model zone has knowndimensions and one or more known materials having a given reflectivitycharacteristic, and wherein the particular pre-determined calibrationoffsets acoustic characteristics of the model zone having knowndimensions and including the one or more known materials having thegiven reflectivity characteristic.
 6. The method of claim 1, wherein theparticular pre-determined calibration is a first type of calibration,wherein the particular pre-determined calibration is based on audioprocessing algorithms determined from multiple calibrations of a secondtype performed in respective zones to approximate the model zone.
 7. Theplayback device of claim 1, wherein the particular pre-determinedcalibration is a first type of calibration, and wherein the methodfurther comprises: after calibrating the playback device with the firsttype of calibration, receiving an instruction to calibrate the playbackdevice with a second type of calibration; based on the instruction tocalibrate the playback device with the second type of calibration,calibrating the playback device with the second type of calibration,wherein calibrating the playback device with the second type ofcalibration comprises: causing the playback device to output calibrationaudio via one or more speakers while a microphone records thecalibration audio output; determining a particular calibration of thesecond type, the particular calibration of the second type based on therecorded calibration audio output such that the particular calibrationof the second type offsets acoustic characteristics of the particularzone in which the playback device is located when applied to theplayback device; and causing the playback device to apply the particularcalibration of the second type in place of the particular pre-determinedcalibration of the first type.
 8. The method of claim 1, furthercomprising: receiving, via the network interface from a control device,data representing instructions to play back particular audio content onthe playback device, wherein causing the playback device to play backaudio comprises causing the playback device to play back the particularaudio content while the particular pre-determined calibration is appliedto the playback device.
 9. The method of claim 1, wherein causing theplayback device to play back audio comprises causing the playback deviceto play back the audio in synchrony with one or more additional playbackdevices.
 10. The method of claim 1, wherein the computing systemcomprises the one or more servers.
 11. A computing system comprising: anetwork interface; at least one processor: at least one non-transitorycomputer-readable medium comprising program instructions that areexecutable by the at least one processor such that the computing systemis configured to: calibrate a playback device, wherein the programinstructions that are executable by the at least one processor such thatthe computing system is configured to calibrate the playback devicecomprises program instructions that are executable by the at least oneprocessor such that the computing system is configured to: determinethat the playback device is in a particular type of zone; query adatabase of pre-determined calibrations for a particular pre-determinedcalibration, the particular pre-determined calibration offsettingacoustic characteristics of a model zone that simulates the particulartype of zone, wherein the model zone is based on additional zonescorresponding to the particular type of zone, and wherein the databaseis hosted by one or more servers remote from the playback device; andcause, via a network interface, the playback device to apply theparticular pre-determined calibration to the playback device; and cause,via the network interface, the playback device to play back audio whilethe particular pre-determined calibration is applied to the playbackdevice.
 12. The computing system of claim 11, wherein the programinstructions that are executable by the at least one processor such thatthe computing system is configured to determine that the playback deviceis in the particular type of zone comprises program instructions thatare executable by the at least one processor such that the computingsystem is configured to: receive audio data recorded via a microphonewhile the playback device played back audio, and determine that theplayback device is in the particular type of zone based on the receivedaudio data.
 13. The computing system of claim 11, wherein the programinstructions that are executable by the at least one processor such thatthe computing system is configured to determine that the playback deviceis in the particular type of zone comprises program instructions thatare executable by the at least one processor such that the computingsystem is configured to: receive, via the network interface from acontrol device, data representing the particular type of zone, whereinthe data is based on user input at the control device indicating theparticular type of zone.
 14. The computing system of claim 11, whereinthe program instructions that are executable by the at least oneprocessor such that the computing system is configured to determine thatthe playback device is in the particular type of zone comprises programinstructions that are executable by the at least one processor such thatthe computing system is configured to: access, from data storage, amodel of the playback device, wherein playback devices of that model areconfigured to be positioned in the particular type of zone; and whereinthe program instructions that are executable by the at least oneprocessor such that the computing system is configured to query thedatabase of pre-determined calibrations for the particularpre-determined calibration comprises program instructions that areexecutable by the at least one processor such that the computing systemis configured to: query the database using the model of the playbackdevice to retrieve the particular pre-determined calibration.
 15. Thecomputing system of claim 11, wherein the model zone has knowndimensions and one or more known materials having a given reflectivitycharacteristic, and wherein the particular pre-determined calibrationoffsets acoustic characteristics of the model zone having knowndimensions and including the one or more known materials having thegiven reflectivity characteristic.
 16. The computing system of claim 11,wherein the particular pre-determined calibration is a first type ofcalibration, wherein the particular pre-determined calibration is basedon audio processing algorithms determined from multiple calibrations ofa second type performed in respective zones to approximate the modelzone.
 17. The computing system of claim 11, wherein the particularpre-determined calibration is a first type of calibration, and whereinthe at least one non-transitory computer-readable medium furthercomprises program instructions that are executable by the at least oneprocessor such that the computing system is configured to: aftercalibration of the playback device with the first type of calibration,receive an instruction to calibrate the playback device with a secondtype of calibration; based on the instruction to calibrate the playbackdevice with the second type of calibration, calibrate the playbackdevice with the second type of calibration, wherein the programinstructions that are executable by the at least one processor such thatthe computing system is configured to calibrate the playback device withthe second type of calibration comprises program instructions that areexecutable by the at least one processor such that the computing systemis configured to: cause the playback device to output calibration audiovia one or more speakers while a microphone records the calibrationaudio output; determine a particular calibration of the second type, theparticular calibration of the second type based on the recordedcalibration audio output such that the particular calibration of thesecond type offsets acoustic characteristics of the particular zone inwhich the playback device is located when applied to the playbackdevice; and cause the playback device to apply the particularcalibration of the second type in place of the particular pre-determinedcalibration of the first type.
 18. The computing system of claim 11,wherein the at least one non-transitory computer-readable medium furthercomprises program instructions that are executable by the at least oneprocessor such that the computing system is configured to: receiving,via the network interface from a control device, data representinginstructions to play back particular audio content on the playbackdevice, wherein causing the playback device to play back audio comprisescausing the playback device to play back the particular audio contentwhile the particular pre-determined calibration is applied to theplayback device.
 19. The computing system of claim 11, wherein theprogram instructions that are executable by the at least one processorsuch that the computing system is configured to cause the playbackdevice to play back audio comprises program instructions that areexecutable by the at least one processor such that the computing systemis configured to: cause the playback device to play back the audio insynchrony with one or more additional playback devices.
 20. Anon-transitory computer-readable medium having stored thereon programinstructions executable by at least one processor of a computing systemto cause the computing system to: calibrate a playback device, whereinthe program instructions that are executable by the at least oneprocessor such that the computing system is configured to calibrate theplayback device comprises program instructions that are executable bythe at least one processor such that the computing system is configuredto: determine that the playback device is in a particular type of zone;query a database of pre-determined calibrations for a particularpre-determined calibration, the particular pre-determined calibrationoffsetting acoustic characteristics of a model zone that simulates theparticular type of zone, wherein the model zone is based on additionalzones corresponding to the particular type of zone, and wherein thedatabase is hosted by one or more servers remote from the playbackdevice; and cause, via a network interface, the playback device to applythe particular pre-determined calibration to the playback device; andcause, via the network interface, the playback device to play back audiowhile the particular pre-determined calibration is applied to theplayback device.